Enhancement of Room-Temperature Low-Field Magnetoresistance in Nanostructured Lanthanum Manganite Films for Magnetic Sensor Applications

Sensors

Skirmantas Kersulis¹  Remigijus Vasiliauskas¹  Nerija Zurauskiene¹  Valentina Plausinaitiene¹  Jorunas Dobilas¹  Voitech Stankevic¹  Milita Vagner¹  Martynas Skapas¹  Mykola Koliada¹  Jaroslaw Pietosa²  Andrzej Wisniewski² 

[1] Center for Physical Sciences and Technology, 10257 Vilnius, Lithuania;Institute of Physics of the Polish Academy of Sciences, 02-668 Warsaw, Poland;

关键词: colossal magnetoresistance;    low-field magnetoresistance;    manganite films;    nanostructured thin films;    MOCVD technology;    magnetic field sensors;   

DOI  :  10.3390/s22114004

来源: DOAJ

【 摘 要 】

The results of colossal magnetoresistance (CMR) properties of La_1-xSr_xMn_yO₃ (LSMO) films grown by the pulsed injection MOCVD technique onto an Al₂O₃ substrate are presented. The grown films with different Sr (0.05 ≤ x ≤ 0.3) and Mn excess (y > 1) concentrations were nanostructured with vertically aligned column-shaped crystallites spread perpendicular to the film plane. It was found that microstructure, resistivity, and magnetoresistive properties of the films strongly depend on the strontium and manganese concentration. All films (including low Sr content) exhibit a metal–insulator transition typical for manganites at a certain temperature, T_m. The T_m vs. Sr content dependence for films with a constant Mn amount has maxima that shift to lower Sr values with the increase in Mn excess in the films. Moreover, the higher the Mn excess concentration in the films, the higher the T_m value obtained. The highest T_m values (270 K) were observed for nanostructured LSMO films with x = 0.17–0.18 and y = 1.15, while the highest low-field magnetoresistance (0.8% at 50 mT) at room temperature (290 K) was achieved for x = 0.3 and y = 1.15. The obtained low-field MR values were relatively high in comparison to those published in the literature results for lanthanum manganite films prepared without additional insulating oxide phases. It can be caused by high Curie temperature (383 K), high saturation magnetization at room temperature (870 emu/cm³), and relatively thin grain boundaries. The obtained results allow to fabricate CMR sensors for low magnetic field measurement at room temperature.

【 授权许可】

Unknown