The magnetic Curie temperature and exchange coupling between cations in tetragonal spinel oxide Mn{sub 2.5}M{sub 0.5}O{sub 4} (M = Co, Ni, Mn, Cr, and Mg) films

Journal Article · Sun Apr 01 00:00:00 EDT 2012 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3672407· OSTI ID:22036848

Kuo, K; Cheng, C W; Chern, G ^[1]

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1. Physics Department and SPIN Research Center, National Chung Cheng University, Chia-Yi, Taiwan, 621 (China)

Mn{sub 3}O{sub 4} is a Jahn-Taller tetragonal ferrite that has a relatively low Curie temperature (T{sub c}) of {approx}43 K due to weak coupling between the canting spins. In this study, we fabricated a series of 100-nm-thick Mn{sub 2.5}M{sub 0.5}O{sub 4} (M = Co, Ni, Mn, Cr, and Mg) films via oxygen-plasma-assisted molecular beam epitaxy and measured the structural and magnetic properties of these films. These films show single phase quality, and the c-axis lattice parameter of pure Mn{sub 3}O{sub 4} is 0.944 nm, with a c/a ratio {approx}1.16, consistent with the bulk values. The replacement of Mn by M (M = Co, Ni, Cr, and Mg) changes the lattice parameters, and the c/a ratio varies between 1.16 and 1.06 depending upon the cation distribution of the films. The magnetic Curie temperatures of these films also vary in the range of 25-66 K in that Ni and Co enhance the T{sub c} whereas Mg reduces the T{sub c} (Cr shows no effect on the T{sub c}). These changes to the T{sub c} are related to both the element electronic state and the cation distributions in these compounds. As a non-collinear spin configuration can induce electrical polarization, the present study provides a systematic way to enhance the magnetic transition temperature in tetragonal spinel ferrites.

• OSTI ID: 22036848
• Journal Information: Journal of Applied Physics, Vol. 111, Issue 7; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
CATIONS
COBALT COMPOUNDS
COERCIVE FORCE
COUPLING
CURIE POINT
ELECTRONS
EXCHANGE INTERACTIONS
HYSTERESIS
JAHN-TELLER EFFECT
LATTICE PARAMETERS
MAGNESIUM COMPOUNDS
MAGNETIC PROPERTIES
MANGANESE OXIDES
MOLECULAR BEAM EPITAXY
PLASMA
POLARIZATION
SPIN
SPINELS
TETRAGONAL LATTICES
THIN FILMS