Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático

In this work, we investigated the magnetic properties of a monocrystalline Fe thin film and of Fe(80 Å)/Cr(t)/Fe(80 Å) tri-layers, with the nonmagnetic metallic Cr spacer layer thickness varying between 9 Å < t < 40 Å. The samples were deposited by the DC Sputtering on Magnesium Oxide (MgO) substrates, with (100) crystal orientation. For this investigation, experimental magneto-optical Kerr effect (MOKE) magnetometry and ferromagnetic resonance (FMR) techniques were employeed. In this case, these techniques allowed us to study the static and dynamical magnetization properties of our tri-layers. The experimental results were interpreted based on the phenomenological model that takes into account the relevant energy terms to the magnetic free energy to describe the system behavior. In the case of the monocrystalline Fe film, we performed an analytical discussion on the magnetization curves and developed a numerical simulation based on the Stoner-Wohlfarth model, that enables the numerical adjustment of the experimental magnetization curves and obtainment of the anisotropy field values. On the other hand, for the tri-layers, we analyzed the existence of bilinear and biquadratic couplings between the magnetizations of adjacent ferromagnetic layers from measurements of magnetization curves. With the FMR fields and line width angular dependencies, information on the anisotropy in three layers was obtained and the effects of different magnetic relaxation mechanisms were evidenced. It was also possible to observe the dependence of the epitaxy of the multilayers with growth and sputtering parameters. Additionally it was developed the technique of AC magnetic susceptibility in order to obtain further information during the investigation of magnetic thin films

Ondas de spin em nanofilmes nagnéticos acoplados quasiperiodicamente

We studied the spin waves modes that can propagate in magnetic multilayers composed of ferromagnetic metallic films in the nanometer scale. The ferromagnetic films (iron) are separated and coupled through the nonmagnetic spacer films (chromium). The films that make up the multilayer are stacked in a quasiperiodic pattern, following the Fibonacci and double period sequences. We used a phenomenological theory taking into account: the Zeeman energy (between the ferromagnetic films and the external magnetic field), the energy of the magneto-crystalline anisotropy (present in the ferromagnetic films), the energy of the bilinear and biquadratic couplings (between the ferromagnetic films) and the energy of the dipole-dipole interaction (between the ferromagnetic films), to describe the system. The total magnetic energy of the system is numerically minimized and the equilibrium angles of the magnetization of each ferromagnetic film are determined. We solved the equation of motion of the multilayer to find the dispersion relation for the system and, as a consequence, the spin waves modes frequencies. Our theoretical results show that, in the case of trilayers (Fe/Cr/Fe), our model reproduces with excellent agreement experimental results of Brillouin light scattering, known from the literature, by adjusting the physical parameters of the nanofilms. Furthermore, we generalize the model to N ferromagnetic layers which allowed us to determine how complex these systems become when we increase the number of components. It is worth noting that our theoretical calculations generalize all the results known from the literature

Crescimento de filmes nanométricos monocristalinos de Fe/MgO(100) por "SPUTTERING" DC

The research behind this master dissertation started with the installation of a DC sputtering system, from its first stage, the adaptation of a refrigerating system, passing by the introduction of a heating system for the chamber using a thermal belt, until the deposition of a series of Fe/MgO(100) single crystal nanometric film samples. The deposition rates of some materials such as Fe, Py and Cu were investigated through an Atomic Force Microscope (AFM). For the single crystal samples, five of them have the same growth parameters and a thickness of 250Å, except for the temperature, which varies from fifty degrees from one to another, from 100ºC to 300ºC. Three other samples also have the same deposition parameters and a temperature of 300ºC, but with thickness of 62,5Å, 150Å, and 250Å. Magneto-optical Kerr Effect (MOKE) of the magnetic curves measurements and Ferromagnetic Resonance (FMR) were made to in order to study the influence of the temperature and thickness on the sample s magnetic properties. In the present dissertation we discuss such techniques, and the experimental results are interpreted using phenomenological models, by simulation, and discussed from a physical point of view, taking into account the system s free magnetic energy terms. The results show the growth of the cubic anisotropy field (Hac) as the sample s deposition temperature increases, presenting an asymptotic behavior, similar to the characteristic charging curve of a capacitor in a RC circuit. A similar behavior was also observed for the Hac due to the increase in the samples thicknesses. The 250˚A sample, growth at 300°C, presented a Hac field close to the Fe bulk value

Two-dimensional modeling of material failure in reinforced concrete by means of a continuum strong discontinuity approach

The paper presents a new methodology to model material failure, in two-dimensional reinforced concrete members, using the Continuum Strong Discontinuity Approach (CSDA). The mixture theory is used as the methodological approach to model reinforced concrete as a composite material, constituted by a plain concrete matrix reinforced with two embedded orthogonal long fiber bundles (rebars). Matrix failure is modeled on the basis of a continuum damage model, equipped with strain softening, whereas the rebars effects are modeled by means of phenomenological constitutive models devised to reproduce the axial non-linear behavior, as well as the bondslip and dowel effects. The proposed methodology extends the fundamental ingredients of the standard Strong Discontinuity Approach, and the embedded discontinuity finite element formulations, in homogeneous materials, to matrix/fiber composite materials, as reinforced concrete. The specific aspects of the material failure modeling for those composites are also addressed. A number of available experimental tests are reproduced in order to illustrate the feasibility of the proposed methodology. (c) 2007 Elsevier B.V. All rights reserved.

A mixture theory based method for three-dimensional modeling of reinforce concrete members with embedded crack finite elements

The paper presents a methodology to model three-dimensional reinforced concrete members by means of embedded discontinuity elements based on the Continuum Strong Discontinuous Approach (CSDA). Mixture theory concepts are used to model reinforced concrete as a 31) composite material constituted of concrete with long fibers (rebars) bundles oriented in different directions embedded in it. The effects of the rebars are modeled by phenomenological constitutive models devised to reproduce the axial non-linear behavior, as well as the bond-slip and dowel action. The paper presents the constitutive models assumed for the components and the compatibility conditions chosen to constitute the composite. Numerical analyses of existing experimental reinforced concrete members are presented, illustrating the applicability of the proposed methodology.

Two-branes with variable tension model and the effective Newtonian constant

It is shown that, in the two brane time variation model framework, if the hidden brane tension varies according to the phenomenological Eotvos law, the visible brane tension behavior is such that its time derivative is negative in the past and positive after a specific time of cosmological evolution. This behavior is interpreted in terms of a useful mechanical system analog and its relation with the variation of the Newtonian (effective) gravitational constant is explored.

Black string corrections in variable tension braneworld scenarios

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reflexões sobre a formação clínica fenomenológico-existencial na era da técnica

Phenomenology is the focus of this study for its critique of the limits of positivist science, which guides most of the fields of study including Psychology. The clinical formation process in Psychology courses is especially difficult for students-interns who adopt phenomenology as their clinical framework. Such difficulty is due to the incompatibility between theory provided in Psychology courses a science traditionally based on paradigms of scientism , and the theoretical-methodological proposal adopted by the aforementioned approach. As a backdrop for our study, we carefully examined the thought of philosopher Martin Heidegger, especially the Era of Technique. This contemporary technicism society was studied so that we could understand the socio-cultural status where this formation lies. Thus, we questioned if this panorama upon which Clinical Psychology rests favors the development of a phenomenological attitude and a special look at the meanings of existence, as defined in phenomenological clinical practice. Knowing such limits, our research aimed at understanding the experience of formation of clinical psychologists who take part in internships in the field of phenomenology-existentialism. Such study was, then, a phenomenological-hermeneutic research based on Heideggerian ontology and used a semi-structured interview as access tool. Six students of the UFRN higher-degree Psychology course who were doing their supervised internship in clinical psychology and the referred approach took part in this research. The research revealed that the phenomenological-existential formation phase opens a door to discoveries on the part of the intern that transcend the dimension of the other, for they show a self disclosure while a person in the word. Despite the initial discomforts caused by the course curriculum itself and by the freedom for clinical practice, so characteristic of phenomenology, the narratives demonstrate that such difficulties may start a process of search for new meanings, which show a search for sharpening their practices and for a path in balance with the existence of the other

Não há você sem mim: histórias de mulheres sobreviventes de uma tentativa de homicídio

The murder-suicide (H / S) has been defined as a shocking crime in which a person takes the life of another and then kills himself within 24 hours. Set up as a gender violence, because men are in majority, the killers and the women victims. This study aims to understand the meanings of the experience of a H / S, from women who have survived this act. This study sets up as a hermeneutic phenomenological research, based on Heidegger`s ontology. We interviewed three survivors of H / S, whose narratives allowed to approach the senses present in their lives. The interviews were transcribed and interpreted in accordance with the hermeneutic circle, as proposed by Martin Heidegger. From the interviews of research participants perceive that these women have built their senses in stocks, represented the family foundation and the presence of a husband and children. This project that moved their lives toward the construction of modes-of-being. We noticed the presence of historicity constructing meanings for the existence of these women. We found reports of an experience of loving relationships characterized by strong jealousy, with the presence of fantasies of betrayal, and marked by a careful affective relationship that put them in the position of object possession of his companions. Reflect that such caring restricted their existence being-for-husband. So the senses that moved their stocks, which aimed his ways existential, was the creation of a family, a reference to their lives, to live a love, and care for the children. Therefore, beyond the already known aspects in studies on violence against women, which made these women continue to choose this relationship was the sense that they had for their existence. It is hoped that this study will contribute to the construction of a new look on violence against women, taking as a basis the Heideggerian hermeneutic phenomenology

Masculinidade a prova: um estudo de inspiração fenomenologico - hermeneutico sobre a infertilidade masculina

Culturally, childbearing is understood as a situation that subjects will experience at some point in their lives, especially people who are married or have a similar affectionate relationship. Thus, to realize the inability to meet such a fate seems to be a natural cultural trigger of suffering, frustration and feelings of inadequacy and helplessness. Specifically for men, infertility is closely related to loss of masculinity, virility. He fails in his role as a male. This study sought to understand the impact that infertility have on the existence of a man who receives such a diagnosis, both in self-image as in their marital, sexual and professional roles. This study sets up as a hermeneutic phenomenological research based on the ideas of the philosopher Martin Heidegger. Participants were seven heterosexual, married and infertile men. Two interviews were conducted. The analysis of the material included both the material of the narratives, as the affectation of the researcher when interacting with the participants and their narratives, through phenomenological-hermeneutic interpretation. The results corroborate the literature that states the difficulty of the men, immersed in a context that defines them as virile, powerful and invulnerable to worry about issues related to health and disease. The possibility of any condition that impairs the reproductive capacity exceeds the acceptable limits of daily life for these men, not being recognized as a model of masculinity present in the condition in which they recognize. This leads to questions about their masculinity, role in the marital relationship and their existence. Thus, to recognize themselves as infertile surpass a medical diagnosis and is associated with the construction of meaning for their existence from the approximation with the infertility condition, which helps in redirecting their choices, restoring the project to be self and allowing further recognition as men. In the marital relationship, doing what they can to ensure, theirs happiness. Through these actions, they remain playing the role of family provider, showing that they are able to protect their wives and taking in assisted reproduction or adoption of children viable alternatives to fulfill the desire to leave a legacy and give a child to their wives and to society. Another result observed, refers to the ontological condition of care that characterizes the human being. The ways in which men are treated socially demonstrates a type of care that focuses on the development of characteristics such as strength, virility and determination but does not allow them to cope with the suffering of emotionally difficult situations, such as the diagnosis of infertility. At the end, the study gives rise to reflections on the need to provide a 12 space for men and their expressions of suffering, as well as to recognize their ability to overcome the painful and difficult situations

Do útero à adoção: a experiência de mulheres férteis que adotaram uma criança

Even with all changes and ruptures related to the social roles that woman had performed, the literature had confirmed that the motherhood still configures it like one of the main roles that she hopes to play in some moment of her life. When the woman did not get pregnant or take ahead a pregnancy, some women find in adoption an alternative to play this role. This research aimed to understand the experience of being mother for adoption in the case of fertile women, but whose partner is infertile. Supported by existential-phenomenological theory, used it the narrative, how methodological instrument. Participated five women, whose adoption process followed the legal ways in the Youngness and Infancy Judgeship of Natal/RN. The results showed that in the selfish training, the woman to see herself how whose role principal is to generate children, although, she think that is natural her participation in others activities go out home too. In male infertile case is a tendency that the woman strikes the infertile status too. The adoption is an alternative to fulfill her desire of being a mother and, meanwhile, please her husband and guarantee the continuity of her love relationship. Through motherly care, the woman discover herself as a mother, what brings a new meaning for her live, independent of to generate a child. Though, exit frustration, sometimes, in association with suffering, on account of the pregnancy and childbirth absence. The end of the research suggests reflections that to become fulfilled herself as mother, the woman does not need, necessarily, to generate a child, being the maternity one of the uncountable possibilities that are shown, and that she can choose, or not, accomplish it

A experiência de adolescentes portadores de diabetes Mellitus Tipo 1: seus significados e sentido

Worldwide, the diabetes mellitus is considered a serious problem of public health; it also involves high costs for its treatment and its complications. Even though the onset of diabetes mellitus type 1 is on 5% to 10% of the diabetic population, it is the most aggressive type of anifestation; furthermore, it is the commonest chronic disease in childhood and adolescence. Such data show the importance of understanding the development of this disease from the moment the individual perceives it, according to their experience, observing the complexity of the phenomenon thoroughly. This study aimed to comprehend the experience of the adolescent with onset of diabetes mellitus type 1 in order to learn how these young individuals perceive and reason their place in the world when they experience this illness. The methodological strategy was based on qualitative research of phenomenological inspiration. We applied the main ideas of heideggerian ontology and some concepts of existential phenomenological psychology to guide our reflexive path. The participants were 10 young individuals (06 female and 04 male), ages between 15 and 18, under treatment in the city of Recife, Pernambuco. The methodological resource was the narrative, which allowed us access to the adolescents experience. The comprehension of the reports was based on the heideggerian hermeneutics, whose priority is the interpretation of the meaning expressed by the participants speech. The results showed that factors such as social, family, economic and cultural context greatly influence the perception and the way the individuals deal with, perceive and reason their experience. We noticed that the diabetes type 1 may often represent a limitation, but it does not make it impossible to be part of the world with others. The data show a significant affective ambivalence regarding the content more directly related to the disease. This demonstrates the unique way which each one gives meaning and reasons their condition of existence. This research points out the need to understand the complexity of this phenomenon in a more complete manner, considering the adolescent in their timely and historical context. We believe we can encourage thinking that may become actions which are more fit to the reality researched regarding all the parties involved with the subject, such as health professionals, adolescents, family, support programs and public health policies

Compreendendo a experiência de pessoas portadoras de transtorno mental: histórias de vidas severinas repletas de possibilidades

This study aims to understand the experience of people suffering from mental disorder. The patients are enrolled in a mental health ambulatory clinic in the city of Natal (RN). Mental disorders are growing rapidly in the contemporary world and are a source of intense mental suffering. Besides patients being strongly marked by a history of isolation and prejudice, they have been the target of real atrocities committed in the name of preservation of a supposed normality. The understanding and treatment of this disorder is influenced by cultural and historical inferences, depending on the period in which it is experienced. Semi-directed Interviews were conducted with a group of users, with the emphasis on giving voice to their uniqueness and individuality, highlighting how each one perceives his or her own experience. These were recorded and later transcribed by identifying the core of meanings. The results were analyzed under the gaze of the Humanist Phenomenology Existential perspective, which aims to unravel the phenomenon, without truths from volatility, highlighting the existence of the mental disorder as a way of living, being permeated by suffering mental and influenced by social problems, assuming contours very particular to each individual. Some progress has been perceived, even by users, with respect to the change of paradigm in the way of care, but still there is a consistent emphasis on medical and drug use. The changes point to the need for offering services to replace the asylum hospital model, and in addition to accept the bearer of mental disorder as a citizen, a bearer of rights who should be accepted and respected by society. Despite the pain expressed and its close liaison with suicide, their reports are full of perspectives and attitudes of confrontation facing life, pointing to new possibilities to be, recreating itself

O médico diante da morte na urgência e emergência:reflexões sobre o ser médico

The literature pointed that the way which people deal with death have been changing along centuries, and nowadays what is realized it is that, each time more, the human being have difficulties to deal with death. Due to the fact that the main function of the physician is to save their patients lives; responsibility that is aggravated by the necessity of to take decisions quickly, once he need to deal with the unexpected situations of the urgency and emergency, many times these professional have to face of impotency and fail situations, when he lose a patient. The main goal of this study was to understand the experience of physicians that work in the urgency and emergency, in front of death. These questioning it justified by the fact of the physicians do not have, many times, a space to express their suffering and anguish about the issues related to death in their work routine, despite lifedeath question to be often present their everyday. It is still possible to verify in the literature, an appointment of the necessity of to include in the curriculum of Medicine courses, subjects that approach such questions. The method used was based on the existential-phenomenological perspective, using as instrument the participant observation, to the intent of understand the routine in the urgency and emergency context, and semi-structured interview. It was interviewed six physicians that work in the urgency and emergency of the most important hospital of public health system of Natal-RN. The results showed that the physicians reported pleasure in work in the urgency and emergency, despite of they presented stress and the difficulties that they deal with in the public system. Despite of the fact that the death to be considered as a phenomenon that make part of the physician s routine, sometimes, deals with these one is more difficult. Many times losses generate an impotency and guilty feeling, as well as questionings about their performance during the attempts to save lives. We verified, from this study, the importance of the existence of some kind of intervention in the emergency, in order to the physicians can elaborate the questions about death and die emerged in their work. We consider yet that this study corroborates and reiterates the discussions concerning the importance of this thematic to be approached in a more effective way, during the academic formation of these professionals, as well as, the importance of a larger investment from the part of Government in the urgency and emergency sector, in order to propitiate to these professionals a work that brings less harmful for their health

O aborto provocado como uma possibilidade na existência da mulher: reflexões fenomenológico-existenciais

Abortion is a very controversial and stigmatized subject, target of many criticism and discussions, mainly regarding to the legal, bioethical and religious aspects involved. In Brazil, abortion is considered a serious public health problem, being the major cause of maternal death due to its criminalization. The woman who causes an abortion is not up looked by society, since motherhood, culturally and historically, was imposed as a destination. Our main goal is to understand, from the existential-phenomenological perspective, the unique experience of the woman who induced the abortion This study is an offshoot of a larger study from USP in partnership with UFRN. Our participants were women who checked in on a maternity hospital in Natal with a miscarriage diagnosis and, among them, those who reported having induced abortion. Altogether, five women were interviewed. The used method was a phenomenological hermeneutics. The research revealed that the experience of abortion is a possibility that permeates women s life, being understood as a choice. This choice pervaded by much suffering, once it goes against everything that women are culturally taught and meant to be. The feeling more surfacing in this experiment, confirming the literature review, was blame. Abortion was also shown as an experience of helplessness and loneliness, due to lack of support from family and the partner. It was also revealed that abortion was made, mainly, by the desire of going along with future projects, including the prosecute of motherhood in the therms of what they consider ideal to a son s arrival, meaning, a family formation grounded on a stable relationship. Regarding the care provided by health professionals to these women, there is the need of restructuring the operating logic of SUS, so that women have the right to health in a integrate manner. This experience also made women reconsider the meanings they had towards abortion, and their life projects