Magnetic Sensors Based on AMR Effect in LSMO Thin Films

Abstract

Abstract:In this paper, the potentialities of the manganese oxide compound La0.7Sr0.3MnO3 (LSMO) for the realization of sensitive room temperature magnetoresistive sensors are discussed. LSMO films deposited on various types of substrates having different magnetic anisotropies were patterned to form rectangular stripes of width 100 µm and length 300 µm. It is shown that, apart from the well-known colossal magnetoresistance contribution, the anisotropic magnetoresistance effects can be used to exhibit competitive performance at room temperature benefiting from the very low noise of LSMO thin films.

Textured Manganite Films Anywhere

“…The strontium content leads to hole doping of the manganite, controlling the charge density at the Fermi level. Notably, LSMO exhibits a colossal magnetoresistance (CMR) and a ferromagnetic-metallic state (FM-M) at room temperature with high T C of 369 K for a substitution rate of ~30% for La, rendering this oxide very interesting for applications as sensor 9,10 , in spintronics [11][12][13][14] and for magneto-optical and optoelectronic applications 15,16 .…”

Sustained coherent epitaxy and role of oxygen vacancies in La0.7Sr0.3MnO3−δthin films grown on SrTiO3by sputtering

“…However, this occurs only at the initial stage of the epitaxial growth when the film is very thin, say, 10 nm thick or so. 4 The critical thickness, above which the influence of the interface diminishes, is usually thought to be much smaller than 180 nm even in the case of LSMO [32] as long as only the interface affinity and the in-plane compressive stress are concerned. This is because the in-plane compressive stress, normally existent in the film crystal structure, becomes dominant over the tensile stress exerted by the interface when the film thickness becomes several tens of times the lattice constant.…”

“…The ferromagnetism of this material derives from the double exchange interaction [2,3], and hence the ferromagnetic transition is accompanied by a metal-insulator transition. At temperatures near the transition, LSMO exhibits a significantly large magnetoresistance, which has been attracting interest in its potential application to sensors [4] and other electronic devices [5][6][7][8]. In addition, perfect spin polarization associated with the double exchange interaction is also attractive for the spin-tunneling devices [5,6,[8][9][10].…”

“…As the growth rate increases, the atomic fluence increases and the number of collisions between radical oxygen atoms and other sputtered atoms increases, reducing the arrival rate for lighter oxygen atoms 3. By 'coherently' we mean that the in-plane lattice constants are the same and dislocations are absent 4. In the case of YBaCuO films grown on MgO, for example, the strain in the YBCO film is relieved when the thickness increases beyond…”

Angle-dependent magnetoresistance in epitaxially strain-engineered thin films

“…LSMO is well known for its applications in magnetic tunnel junctions with TMR values of 83% in the first report by Lu et al [59] in 1996. Due to its display of magnetic properties above room temperature, LSMO is predicted to be a good candidate for low noise magnetoresistance sensors [60]. Tuning growth parameters, like background gas pressure or substrate temperature, allows us to alter material parameters like thickness, oxygen deficiency, strain, and crystallinity of the thin films to influence the magnetotransport properties.…”