• Schlom, D. G.
• Muller, D.
• Brooks, C. M.
• Schubert, J.
• Liu, Z. K.
• Schiffer, P.
• Mundy, J. A.
• Heeg, T.

Abstract

LuFe<SUB>2</SUB>O<SUB>4</SUB> is an exotic material with a simultaneous existence of ferroelectricity and ferrimagnetism at the highest temperature (240 K) of any known material [1]. 25 nm thick films of this unusual multiferroic were grown by MBE on MgAl<SUB>2</SUB>O<SUB>4</SUB>, MgO, and SiC substrates. XRD shows that the LuFe<SUB>2</SUB>O<SUB>4</SUB> films are single-phase and epitaxial. Film stoichiometry was regulated using an adsorption controlled growth process by depositing LuFe<SUB>2</SUB>O<SUB>4</SUB> in an iron rich environment at pressures and temperatures where the excess iron desorbs from the film surface during growth. STEM images reveal the layered structure of LuFe<SUB>2</SUB>O<SUB>4</SUB> and a clean substrate-film interface free of second phases. The magnetization data exhibits a rapid increase in magnetization below 240 K consistent with the bulk paramagnetic to ferrimagnetic phase transition. On further cooling, the zero field cooled (ZFC) branch of the magnetization displays a peak at 205 K that is suggestive of a glassy transition, which is also seen in bulk samples. At 100 K and 70 kOe, we observe a saturation magnetization of 2.4 μ<SUB>B</SUB>/ f. u. (theoretical value of 3 μ<SUB>B</SUB>/ f. u.) [4pt] [1] Ikeda et. al., Nature 436 (2005) 1136--1138....

Topics

• impedance spectroscopy
• surface
• phase
• x-ray diffraction
• layered
• phase transition
• iron
• magnetization
• saturation magnetization