Observation of unusual magnetic behavior: Spin reorientation transition in thick Co–Fe–Ta–B glassy films

Abstract

Effects of transition metal substitution on the glass-formation ability and magnetic properties of Fe 62 Co 9.5 Nd 3 Dy 0.5 B 25 glassy alloy Atomically smooth Co-Fe-Ta-B glassy films were deposited on variety of substrates ͑Si, SiO 2 , and keptone͒. An extensive magnetic characterization in the temperature range from 5 to 330 K is reported for the films of thickness up to ϳ5.5 m. A reversible spin reorientation transition ͑SRT͒ from in-plane single domainlike state to out-of-plane multidomain state with increase in measuring temperature from 5 to 330 K was observed in the films of thickness up to ϳ2.5 m, in contrast to previously reported ultrathin ferromagnetic films of transition metals consisting of about half a dozen of monolayers. The SRT temperature ͑T SRT ͒ is dependent on the film thickness and the applied magnetic field and is not governed by the temperature dependent magnetocrystalline anisotropy or the anisotropy at the film-substrate interface, which are the most common cause for the SRT in magnetic materials. Atomic relaxation has significant influence on SRT. The relaxed state results in a shift in T SRT to higher temperature or disappearance of SRT. We have compared our results with the reported data on ultrathin ferromagnetic films and shown that the atomic randomness and the strains/stress are responsible for the SRT in present case.

Ab initiomolecular dynamics model for density, elastic properties and short range order of Co–Fe–Ta–B metallic glass thin films

“…This property combination enables the application thereof as structural as well as magnetic material. Potential applications for Co 43 Fe 20 Ta 5.5 B 31.5 as magnetic material are magnetic head cores, thin film inductors, transformer cores as well as quick-response magnetic sensors [4,8].…”

On the growth and magnetic properties of flower-like nanostructures formed on diffusion of FePt with Si substrate

“…A pronounced peak at $ 80 K in M(T) curves and a large value of saturation magnetic field in the hysteresis loop measured at 5 K are noticeable. In the first appearance, the observed magnetic features resembled with the materials exhibiting (1) superparamagnetism [42,43], (2) a spin reorientation tranistion (SRT) from out of plane to inplane with increasing temperature [44], and (3) a mixture of ferromagnetic and antiferromagnetic phases [45][46][47][48][49][50]. If the films are superparamagnetic, peak in ZFC and FC should shift toward the lower temperature with measurements performed under higher magnetic fields.…”

“…Additionally, high values of H c ($ 110 Oe) and M r /M s ($ 0.53) at room temperature are inconsistent with the superparamagnetic nature. Existence of SRT in the present films, can be ruled out based on the fact that the SRT temperature (T SRT ) is magnetic field dependent [44], and in the present case the peak position is independent of magnetic field ( Fig. 9(a)).…”

Preferentially Oriented Growth of L10FePt on Si Substrate

“…Metallic glasses do not have a crystal structure, therefore there is no concept of lattice parameters [6]. But if we notice the XRD curve of glassy CoFeTaB layer (Fig.…”