Rudolfine Menzel as a young women Portraits Women

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Rudolfine Menzel with her parents-in-law Portraits Family

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Studio portrait of seven of David Gruenspecht and Rebecca Gruenspecht nee Hoffman's ten children Portraits Family

Includes Louis Gruenspecht, Max Gruenspecht, Abraham (Adolf) Gruenspecht, Babette Gruenspecht, Isaac Gruenspecht, Moses (Moritz) Gruenspecht and Michael Gruenspecht; Missing are Rosalie Gruenspecht, Sarah Gruenspecht and Hirsch Gruenspecht

Studio portrait of David Gruenspecht and Rebecca Gruenspecht nee Hoffman with one of their young sons Portraits Family

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Unidentified Group at Swimming Pool; Pioneer Youth Camp Portraits Groups

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Rudolph, Josie Portraits Women

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Portrait of Walter Landauer Portraits Men

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Ernst Mathias Portraits; Men

Ernst Mathias: born October 13, 1886 in Koenigsberg, Prussia; died October 27, 1971 in Madison, Wisconsin

Ernst Mathias Military; World War I; Portraits

Feldpost to wife Emmy Mathias; April 24, 1916

Ernst Mathias with military doctors, nurses and patients Military; World War I; Portraits; Groups

Feldpost to wife Emmy Mathias; September 19, 1918

Quasi-2D XY Magnetic Properties and Slow Relaxation in a Body Centered Metal Organic Network of [Co-4] Clusters

Octahedral Co2+ centers have been connected by mu(3)-OH and mu(2)-OH2 units forming [Co-4] clusters which are linked by pyrazine forming a two-dimensional network. The two-dimensional layers are bridged by oxybisbenzoate (OBA) ligands giving rise to a three-dimensional structure. The [Co-4] clusters bond with the pyrazine and the OBA results in a body-centered arrangement of the clusters, which has been observed for the first time. Magnetic studies reveal a noncollinear frustrated spin structure of the bitriangular cluster, resulting in a net magnetic moment of 1.4 mu B per cluster. For T > 32 K, the correlation length of the cluster moments shows a stretched-exponential temperature dependence typical of a Berezinskii-Kosterlitz-Thouless model, which points to a quasi-2D XY behavior. At lower temperature and down to 14 K, the compound behaves as a soft ferromagnet and a slow relaxation is observed, with an energy barrier of ca. 500 K. Then, on further cooling, a hysteretic behavior takes place with a coercive field that reaches 5 Tat 4 K. The slow relaxation is assigned to the creation/annihilation of vortex-antivortex pairs, which are the elementary excitations of a 2D XY spin system.

Arthur Segal Portraits Men

Dedication by Arthur Segal: Anneliese u. Niko Braun in herzlichster Liebe und Freundschaft. Arthur Segal. Juni 1924

Edna and Moses Stern with daughters Erna and Annie Portraits Family

Grandparents of Margot Gerson

Martin Riesenburger portrait portraits men

Martin Riesenburger (May 14, 1896 – Apr. 14, 1966) was Prediger (Preacher) for the Jewish community in Berlin-Weissensee throughout the Nazi era (protected by his gentile wife, Natalie Riesenburger). In 1953 he became Rabbi of the Jewish community in Berlin (East) and then Landesrabbiner of the German Democratic Republic.