Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 35: Magnetic Oxides and Shape Memory Alloys (jointly with MM)

MA 35.2: Talk

Thursday, March 14, 2013, 09:45–10:00, H23

First order ferromagnetic to antiferromagnetic transition in the Heusler compounds Fe2MnGa and Mn2PtGa — •A. K. Nayak¹, C. Shekhar¹, T. Gasi², M. Nicklas¹, and C. Felser¹ — ¹Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany. — ²Institut for Inorganic and Analytical Chemistry, Johannes Gutenberg University, 55099 Mainz, Germany

The discovery of ferromagnetism by Heusler in X2YZ based materials that consist of all nonmagnetic elements has led to finding of several new materials with distinguishable properties. However, the structural and magnetic properties of these materials are complex in nature due to the observation of various magnetic as well as structural ordering depending upon the nature of X, Y and Z atoms. The off-stoichiometry X2YZ based materials, where part of the Z atoms are replaced by Y atoms, show a structural transition with strong magneto-structural coupling. Here we will show the observation of first order magnetic to magnetic transition in the Heusler compounds Fe2MnGa and Mn2PtGa. Fe2MnGa crystallizes in a cubic structure with ferromagnetic (FM) ordering that shows large Curie temperature (TC) of 750K. It undergoes a first-order FM to antiferromagnetic(AFM) transition around the room temperature. Mn2PtGa, which crystallizes in tetragonal structure, undergoes a first-order FM to AFM transition around 150K, below the magnetic ordering temperature of 230K. The first-order FM to AFM transition leads to kinetic arrest of the FM to AFM transition. The observation of phase coexistence and field induced irreversibility results in a new phase termed as magnetic glass.