ISSN:
1090-6509
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract A study is performed of the crystalline structure, magnetization, and magnetotransport properties of the system La2/3Ba1/3(Mn1−x Cox)O3 with perovskite structure. It is shown that cubic solid solutions exist over the entire range of cobalt concentrations 0⩽x⩽1. Compositions with x⩽0.2 are ferromagnets with maximum resistance near T C . Compositions with 0.2〈x〈0.4 manifest properties of inhomogeneous ferromagnets. Measurements of magnetic properties indicate the absence of long-range magnetic order in compositions with 0.5⩽x⩽0.9, which are probably spin glasses. The spontaneous magnetization of cobaltate (2μ B per formula unit) corresponds to ferromagnetic ordering of the moments of the Co3+ and Co4+ ions found in the intermediate spin state. It is conjectured that the magnetoresistance consists of an extrinsic and an intrinsic contribution. The first arises as a result of intergrain transport of spin-polarized charge carriers, and the second, as a result of magnetic ordering near T C . The magnetoresistance is essentially independent of the spontaneous magnetization and decreases abruptly as the cobalt concentration is increased with a corresponding transition from long-range to short-range magnetic order.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1134/1.558986
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