Exchange-biasing phenomenon can induce an evident unidirectional hysteresis loop shift by spin coupling effect in the ferromagnetic (FM)/antiferromagnetic (AFM) interface which can be applied in magnetoresistance random access memory (MRAM) and recording-head applications. However, magnetic properties are the most important to AFM texturing. In this work, top-configuration exchange-biasing NiFe/IrMn(x Å) systems have been investigated with three different conditions. From the high-resolution cross-sectional transmission electron microscopy (HR X-TEM) and X-ray diffraction results, we conclude that the IrMn (111) texture plays an important role in exchange-biasing field (Hex) and interfacial exchange energy (Jk).HexandJktend to saturate when the IrMn thickness increases. Moreover, the coercivity (Hc) dependence on IrMn thickness is explained based on the coupling or decoupling effect between the spins of the NiFe and IrMn layers near the NiFe/IrMn interface. In this work, the optimal values forHexandJkare 115 Oe and 0.062 erg/cm2, respectively.

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The two deposition conditions are (a) Si(100)/Fe40Pd40B20(X Å)/ZnO (500 Å) and (b) Si(100)/ZnO(500 Å)/Fe40Pd40B20(Y Å), where X and Y are 25 Å, 50 Å, 75 Å, and 100 Å. The sputtering sequence and the thickness of the FePdB film were varied to examine their effects on the low-frequency alternative-current magnetic susceptibility (χac), maximum phase angle (θmax), maximum χac with corresponding optimal resonance frequency (fres), and electrical resistivity (ρ). Experimental results show that ZnO(500 Å)/Fe40Pd40B20(Y Å) is superior to Fe40Pd40B20(X Å)/ZnO(500 Å) because the ZnO(002) texture at the bottom can improve the magneto nanocrystalline anisotropy of Fe40Pd40B20, improving its magnetic properties. In particular, a comparison of high-resolution cross-sectional transmission electron microscopy observations of Fe40Pd40B20(100 Å)/ZnO(500 Å) and ZnO(500 Å)/Fe40Pd40B20(100 Å) demonstrates that the ZnO(002) texture induces a magneto nanocrystalline anisotropy in the nanocrystalline FePdB layer of ZnO(500 Å)/Fe40Pd40B20(100 Å), yielding a highest χac of approximately 2.8 with an fres of 1000 Hz and an θmax of 169°. Additionally, the ρ is reduced as the FePdB thickness increases, because grain boundaries and the surface of thin films scatter the electrons, so thinner films have a greater resistance. The ρ of ZnO(500 Å)/Fe40Pd40B20(Y Å) is lower than that of Fe40Pd40B20(X Å)/ZnO(500 Å) because stronger ZnO crystallization and nanocrystalline FePdB improve the scattering of electrons by the surface of the films.

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The magnetotransport properties of La0.75Sr0.25MnO3 (LSMO) films epitaxially grown on SrTiO3 (0 0 1) substrate were studied. The Curie temperature (Tc) of LSMO films decreases from 300 to 105 K with a reduction in the film thickness to 5 nm. A clear metal–insulator transition is observed at a temperature consistent with Tc for films thicker than 10 nm. However, the 5 nm thick film displays an insulative characteristic along with a high magnetoresistence effect in a wide range of temperatures below and above Tc. A phase-separation phenomenon in the 5 nm thick film was demonstrated by thermally activated hopping transport between ferromagnetic metallic domains embedded in an insulative matrix at temperatures below Tc, but between paramagnetic metallic domains at temperatures above Tc. It was also confirmed by conductive atomic force microscopy images.

Saturation magnetostriction (λs) of CoFeB∕AlOx∕Co magnetic tunnel junctions (MTJs) has been measured. There are three kinds of MTJs in this study, i.e., glass∕CoFeB(tA)∕AlOx(δto)∕Co(tB) with tA+tB=150Å; tA=100, 75, and 50Å; and δto=0–30Å. When plotting λs as a function of δto, the curve is concave up. We also investigated the compositional distribution of Fe, Al, and O across the tunneling part of the CoFeB(75Å)∕AlOx∕Co(75Å) junction. Based on these results, we propose a model to describe how the total λs is affected by the CoFeB∕AlOx and AlOx∕Co interfaces.

When B and V are added to CoFe material, the mechanical strength and spin tunneling polarization of a CoFe alloy can be improved and enhanced by the high tunneling magnetoresistance (TMR) ratio. Based on these reasons, it is worthwhile investigating Co40Fe40V10B10 films. In this work, X-ray diffraction (XRD) showed that Co40Fe40V10B10 thin films have some distinct phases including CoFe (110), CoFe (200), FeB (130), and V (110) diffracted peaks with the strongest diffracted peak for 30 nm. The lowest low-frequency alternate-current magnetic susceptibility (χac) was detected at 30 nm because the large grain distribution inducing that high coercivity (Hc) enhances the spin coupling strength and low χac. The external field (Hext) had difficulty rotating in the spin state, hence, the spin sensitivity was reduced and the χac value decreased due to increased surface roughness. The 20 mm thickness had the highest χac 1.96 × 10−2 value at 50 Hz of an optimal resonance frequency (fres). The surface energy increased from 34.2 mJ/mm2 to 51.5 mJ/mm2 for Co40Fe40V10B10 films. High surface energy had corresponding strong adhesive performance. According to the magnetic and surface energy results, the optimal thickness is 20 nm due as it had the highest χac and strong adhesion.