High-temperature ferromagnetic insulating phase in strained La_0.8Sr_0.2MnO₃ thin films

Abstract

The effect of misfit strain on the magnetism and electrical conductivity of La 0.8 Sr 0.2 MnO 3 (LSMO(8/2)) thin films was studied. It was observed that properly small strains (−1.35% to +0.26%) could obviously improve the Curie temperature of LSMO(8/2) films with prominent saturated magnetization (up to 576 emu/cm 3 ). An insulating phase with a wide temperature range (10-400 K) has been achieved for largely strained LSMO(8/2) films. These results could inspire a new direction in developing high-temperature magnetic insulators, which are beneficial to applications of manganite films as promising spintronic devices.

Influence of Thickness on the Magnetic and Magnetotransport Properties of Epitaxial La0.7Sr0.3MnO3 Films Deposited on STO (0 0 1)

“…In thin film geometry, the film thickness also plays an important role in influencing the Curie temperature. An increase of T C with thickness for La 0.7 Sr 0.3 MnO 3 films on STO (0 0 1) was reported for thicknesses in the range of 3-40 unit cells (1.2-16 nm; cell parameter ~0.4 nm), from 80 K (1.2 nm) to 320 K (16 nm) [46] and for La 0.8 Sr 0.2 MnO 3 films on LSAT between 250 and 350 K for thicknesses between 7 and 43 nm [47]. A severe reduction of T C with thickness [48] or non-monotonic variations [49] can be related to strain, stress relaxation, and defects.…”