Design of a vector magnet for the measurements of anisotropic magnetoresistance and rotational magneto-optic Kerr effect

Abstract

A vector magnet is designed and assembled with two electromagnets to produce a rotational magnetic field in any direction within a plane. This design allows a rotation of the magnetic field without a mechanical rotation of the magnets. The fast speed of the field rotation (~10 s for a complete 360° rotation) and the stability against mechanical vibration easily overcome the slow drifting effect in anisotropic magnetoresistance (AMR) and rotational magneto-optic Kerr effect (ROTMOKE) measurements. As an example we applied this vector magnet to carry out AMR and ROTMOKE measurements on epitaxial growth of Fe(10 nm)∕MgO(001) films. The result demonstrates the stability and high quality of the vector magnet in determining the magnetic anisotropy of magnetic thin films using AMR and ROTMOKE techniques.

Determination of magnetic anisotropy constants in Fe ultrathin film on vicinal Si(111) by anisotropic magnetoresistance

“…Therefore, the metallic Fe single crystal film gown on iron silicide buffer layer and Si(111) surface provides an ideal system to perform AMR measurements. In the case of Fe single-crystalline system, the AMR can be expressed as20212223242526: where φ M is the angle between the Fe magnetization M Fe and the current flow I , and is the resistance at φ M = 0° and φ M = 90°, respectively.…”

“…On the other hand, the AMR results demonstrate that the symmetry of magnetocrystalline anisotropy energy changes from the six-fold to a superposition of six-fold, four-fold and a weakly uniaxial contribution due to the tiny misorientation from Fe(111) plane. Although the use of AMR to measure the magnetic anisotropy was introduced long time ago20212223242526, to our knowledge, a precise determination of various magnetic anisotropy constants of Fe(111) film on Si(111)-7 × 7 surface with so small miscut angle was not reported in literature. The fitted value of the first-order magnetocrystalline anisotropy K 1 is significantly influenced by the tiny variation of miscut angles β .…”

“…Since the coherent domain rotation magnetization reversal for ultrathin film is not always occurred, especially when the applied field is lower than saturation field, the detailed information regarding the magnetic anisotropy cannot be distinguished precisely from the magnetization hysteresis loops. Alternatively, magnetoransport method has been proved to be an ideal probe of magnetic anisotropy constants in the thin single layer films by anisotropic magnetoresistance (AMR)20212223242526, which determines the anisotropy field strength by realization of a coherent magnetization reversal (Stoner-Wohlfarth-like). This can be achieved by applying a sufficiently large field to guarantee a true single-domain rotation.…”

Tailoring the magnetic anisotropy of Py/Ni bilayer films using well aligned atomic steps on Cu(001)

“…After the MOKE hysteresis loop measurement, the sample was taken out of the UHV chamber and measured using a table top rotation MOKE (ROTMOKE) setup. A detailed description of our ROTMOKE setup was reported previously38. All MOKE and ROTMOKE measurements were performed at room temperature.…”

Strain-Driven Nanoscale Phase Competition near the Antipolar–Nonpolar Phase Boundary in Bi0.7La0.3FeO3 Thin Films

“…Magnetic hysteresis loop measurements were carried out using the longitudinal MOKE. 44 X-ray spectroscopy measurements were carried out at beamline 4.0.2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. The measurements were performed in totalelectron-yield geometry.…”