Tunable magnetic low-frequency noise in magnetic tunnel junctions: effect of shape anisotropy.

The intrinsic magnetic low-frequency noise (LFN) is of fundamental scientific interest to the study of magnetic tunnel junctions (MTJs). To gain insight into its mechanism, the fluctuation-dissipation theorem, which describes the linear relation between magnetic LFN and magnetic sensitivity product, has been utilized. However, deviation from the linear correlation has been reported in some studies.

Magnetoelastic Effects in Doubly Clamped Electroplated CoFe Microbeam Resonators.

Magnetostrictive CoFe films are fully suspended to produce free-standing, clamped-clamped, microbeam resonators. A negative or positive shift in the resonant frequency is observed for magnetic fields applied parallel or perpendicular to the length of the beam, respectively, confirming the magnetoelastic nature of the shift. Notably, the resonance shifts linearly with higher-bias fields oriented perpendicular to the beam's length.

Improvement of Reproducibility of Magnetic Moment Detected by a SQUID Magnetometer Through Radial Offset Measurement on a YIG Sphere.

We report here on the reproducibility of measurements on a second-order gradiometer superconducting quantum interference device magnetometer of two different yttrium iron garnet spheres, both having a diameter of 1 mm: 1) the National Institute of Standards and Technology magnetic moment standard reference material (SRM) and 2) a commercial sample. It has been suggested that rotating the sample rod around its axis can move the sample center toward the center of the second-order gradiometer coil. The observed value of the magnetic moment will be theoretically a minimum when the radial offset is 0, and this value will increase in a "quadratic" manner with the radial offset.

Large magneto-optical Kerr effect and imaging of magnetic octupole domains in an antiferromagnetic metal.

When a polarized light beam is incident upon the surface of a magnetic material, the reflected light undergoes a polarization rotation. This magneto-optical Kerr effect (MOKE) has been intensively studied in a variety of ferro- and ferrimagnetic materials because it provides a powerful probe for electronic and magnetic properties as well as for various applications including magneto-optical recording. Recently, there has been a surge of interest in antiferromagnets (AFMs) as prospective spintronic materials for high-density and ultrafast memory devices, owing to their vanishingly small stray field and orders of magnitude faster spin dynamics compared to their ferromagnetic counterparts.