Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 11: Magnetic Heuslers, Half-Metals and Oxides (jointly with MA)

TT 11.12: Talk

Monday, March 16, 2015, 12:30–12:45, H 0112

Antiferromagnetic order in CuMnSb crystal and its stability — •Frantisek Maca, Vaclav Drchal, and Josef Kudrnovsky — Institute of Physics ASCR, Praha, Czech Republic

It is well known that the ground state of the CuMnSb is antiferromagnetic with alternating ferromagnetic layers in the <111> direction - the AFM(111) structure. The first ab initio calculations comparing nonmagnetic, ferromagnetic and AFM(111) structures [1] also have shown that the antiferromagnetic state has the lowest total energy. However, we found by using FLAPW and TB-LMTO calculations that the ideal AFM(001) structure has always lower total energy than the AF(111).

Experimental measurements show a high resistivity of CuMnSb samples which indicates the presence of disordered impurities. We compare formation energies for various defects in order to find the type of disorder which favors the AFM arrangement. Calculations indicate as the most probable candidate the Mn-Cu swapping. We show that presence of disorder and electron correlations are needed for realistic theoretical description. The total energy results are supported by discussion of magnetic exchange interactions.

[1] T. Jeong, Ruben Weht, and W. E. Pickett, Phys. Rev. B 71, 184103 (2005).