Coherent Ferromagnetic Precipitate and Anomalies in the Heat Conduction and Thermopower of Mn2-xCrxSb Single Crystals

A. Kattwinkel, E. Kraus, Ch. Kleeberg, T. Groń, and K. Bärner 4. Phys. Institut der Universität Göttingen, Bunsenstr. 13-15, 37073 Göttingen, Germany

Received: November 11, 1997; in final form March 17, 1998

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The heat diffusivity D, the electrical resistivity ρ and the thermoelectric power S of tetragonal Mn2-xCrxSb single crystals with 0.02 < x < 0.12 have been measured in the temperature range of 90 K < T < 350 K and along different crystal axes. The heat conductivity κ and σ = 1/ρ are anisotropic along the crystal axes a, c with a ratio of 2:1. κ(T) , ρ(T) and S(T) show anomalies at the spin reorientation temperature TRm of the matrix (M) Mn2-xCrxSb, but also at that of the coherent ferromagnetic precipitate (P) Mn1.037Cr0.11Sb, TRp which is assigned to variations in the spin dependent scattering at the M/P interfaces via changes in the relative orientation of the magnetization vectors of matrix and precipitate (spin valve effect).

DOI: 10.12693/APhysPolA.93.745 PACS numbers: 75.30.Kz, 72.15.Eb, 72.15.Jf