FWI Institutskolloquium: "Tetragonal Heusler compounds for spintronics"

Date

Jul 19, 2012

Time

2:00 PM - 3:30 PM

Speaker

Prof. Dr. Claudia Felser, Director of Max Planck Institute for Chemical Physics of Solids, Johannes Gutenberg University Mainz

Language

en

Main Topic

Physik

Other Topics

Physik

Host

Susann Gebel (2345)

Description

Abstract: Heusler compounds are a remarkable class of materials with more than 1,000 members and a wide range of extraordinary multifunctionalities including half-metallic high-temperature ferri- and ferromagnets, multiferroic shape memory alloys, and tunable topological insulators with a high potential for spintronics, energy technologies and magnetocaloric applications. Recent development of efficient spintronic devices is based on the spin transfer torque (STT) phenomenon. In 2007 Mn3-xGa was identified as a potential electrode for STT applications [1]. In general tetragonal Heusler compounds Mn2YZ as potential materials for STT applications can be easily designed by positioning the Fermi energy at the van Hove singularity in one of the spin channels [2]. The Mn3+ ions in Mn2YZ causes a Jahn Teller distortion. A high calculated magnetic anisotropy energy (MAE) is the sufficient condition for a material with perpendicular magnetocrystalline anisotropy (PMA). Materials with saturation magnetizations (MS) of 0.2 – 4.0 µB, high Curie temperatures (TC) of 380 – 800 K, high spin polarizations, PMA, and required lattice constant matching with MgO can be realized with ferri- or ferromagnetic Heusler-related compounds. Such materials are strongly recommended for the spin transfer torque magnetic random access memory (STT-MRAM) data storage and the spin torque oscillators (STO) for telecommunication. Additional properties can be designed in tetragonal Heusler compounds with three magnetic sublattices. Mn2PtIn is a tetragonal Heusler compound with a large exchange bias behavior. This property likely originates from the glassy nature of the low temperature magnetic state, as indicated by ac susceptibility and zero-field-cooled relaxation measurements [3]. Acknowledgement: T. Gasi, K. Filsinger, B. Balke, G. H. Fecher, C.A. Jenkins, A. Gupta, Li Gao, J. Kübler, G. D. Liu, S. S. P. Parkin References [1] Mn3Ga, a compensated ferrimagnet with high Curie temperature and low magnetic moment for spin torque transfer applications, Benjamin Balke, Gerhard H. Fecher, Jürgen Winterlik, and Claudia Felser, Appl. Phys. Lett. 90 (2007) 152504. [2] Tuning the magnetism of the Heusler alloys Mn3-xCoxGa from soft and half-metallic to hard-magnetic for spin-transfer torque applications, Vajiheh Alijani, Jürgen Winterlik, Gerhard Fecher, and Claudia Felser, Appl. Phys. Lett. 99 (2011) 222510 [3] Exchange bias behavior in a new tetragonal Heusler compound Mn2PtIn, Ajaya K. Nayak, Chandra Shekhar, Jürgen Winterlik, Arunava Gupta, and Claudia Felser, Appl. Phys. Lett. 100 (2012) 152404

Last modified: Jul 19, 2012, 9:35:05 AM