Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 32: Spin Structures and Magnetic Phase Transitions

MA 32.10: Vortrag

Mittwoch, 18. März 2015, 17:30–17:45, EB 202

Magnetic properties of a new phase of MnSb₂O₆ — •Johannes Werner¹, Michael Tzschoppe¹, Changhyun Koo¹, Vladimir B. Nalbandyan², Alexey Yu. Nikulin², Elena A. Zvereva³, and Rüdiger Klingeler¹ — ¹Kirchhoff Institute for Physics, Heidelberg University, Heidelberg, Germany — ²Chemistry Faculty, Southern Federal University, Rostov-na-Donu, Russia — ³Moscow State University, Moscow, Russia

Magnetic properties of a new, layered, trigonal (P31m) form of MnSb₂O₆ were investigated by means of magnetic susceptibility and high-frequency electron spin resonance (HF-ESR) measurements. The magnetic susceptibility at high temperatures follows the Curie-Weiss law, with a Weiss temperature of Θ=−17K, indicating antiferromagnetic interactions. Indeed, long range antiferromagnetic order appears at T_N=9K. In addition, the data imply weak ferromagnetism below T₁=41.5K. Based on the magnetic susceptibility and specific heat data the magnetic phase diagram of the new MnSb₂O₆ form is constructed. The spin-flop field of 1T in the antiferromagnetically ordered phase signals only a small anisotropy which is confirmed by our HF-ESR data. In addition, there is a phase boundary in the non-spin-flopped phase separating two regions of antiferromagnetic order. At this boundary, there are only negligible entropy changes. In HF-ESR, the antiferromagnetic resonance mode is observed and spin wave theory is applied to model the results.