Study of colossal magnetoresistance and pressure effects in La2/3Ca1/3MnO2 thin films /

The main purpose of this thesis is to study properties of La2/3Cai/3Mn03, both polycrystalline ceramics and thin films. This material has striking related electrical and magnetic properties. Thin films show colossal negative magnetoresistance (CMR) near transition from an insulating to a metallic state accompanied closely by transition from a paramagnetic to a ferromagnetic state. The double exchange mechanism (DE) and the Jahn-Teller deformations play an important role in CMR effect. Applied pressure has a very similar effect as does an applied magnetic field, except, at low temperatures (T

Study on the properties of piezoelectric materials and manganese-based oxide perovskites /

Perovskite type piezoelectric and manganese oxide materials have gained a lot of attention in the field of device engineering. Lead zirconium titananium oxide (PbZri.iTiiOa or PZT) is a piezoelectric material widely used as sensors and actuators. Miniaturization of PZTbased devices will not only perfect many existing products, but also opens doors to new applications. Lanthanum manganese oxides Lai-iAiMnOa (A-divalent alkaline earth such as Sr, Ca or Ba) have been intensively studied for their colossal magnetoresistance (CMR) properties that make them applicable in memory cells, magnetic and pressure sensors. In this study, we fabricate PZT and LSMO(LCMO) heterostructures on SrTiOa substrates and investigate their temperature dependency of resistivity and magnetization as a function of the thickness of LSMO(LCMO) layer. The microstructure of the samples is analysed through TEM. In another set of samples, we study the effect of application of an electric field across the PZT layer that acts as an external pressure on the manganite layer. This verifies the correlation of lattice distortion with transport and magnetic properties of the CMR materials.

Letter - Lieut A. Watson Sime to Col. F.C. McCordick

A letter from Lieut. A. Watson to Col. F.C. McCordick dated only July 3rd. The letter reads "My dear Col. McCordick, If you haven't already heard, you will be surprised to get this letter from me - in Germany. It happened at that awful slaughter - the 3rd battle of Ypres, & even now when I think of it all, I doubt my reality of existence. Everything was O.K at 730am on the 2nd - a little morning hate in the way of trench mortars, that was all. I had just visited a few of my guns & had passed Gen.s Mercer & Williams & their aides, Lyman Gooderham and Fraser (two latter at this camp) on the way to the -- C.M.R Bn. Head Quarters when the storm broke. It last for 5 hours & by the time the Germans came over there were few left to oppose them. By a miracle, the 15 yard bay of the front line, where I was with 6 others, was not levelled like all the rest of the line & we did our best with rifle & bomb. I got a crack on the head & 3 hours later I found myself in a waterfilled shell hole. By night I tried to crawl back & through, but at dawn was caught. Am very comfortable here & glad to have company of Col. Usher, Capt. Light Bourne, Capt. Frank Park M.O. -- CMR) & about 20 other Canadians. Hope all is well with you & 35 - Good luck & best regards to all. A. Watson Sime, Lieut. Haus 62-B OFFIZIER-KRIEGSGEFANGENLAGER Gutersloh.