In situ compensation method for high-precision and high-sensitivity integral magnetometry

Abstract

The ongoing process of the miniaturization of spintronics and magneticfilms-based devices, as well as a growing necessity for basic material research place stringent requirements on sensitive and accurate magnetometric measurements of minute magnetic constituents deposited on large magnetically responsive carriers. However, the ever so popular commercial integral magnetometers based on superconducting quantum interference device sensor are not object-selective probes. Therefore, the sought signal is usually buried in the magnetic response of the carrier, contaminated by signals from the sample support, system instabilities and additionally degraded by inadequate data reduction. In this report a comprehensive method based on in situ magnetic compensation by sample abutting long strips made of matching material is shown to provide means for mitigating all these weak elements of integral magnetometry. Practical solutions and proper expressions to calculate the absolute values of the investigated moments are given. Their universal form allows to employ the suggested design in investigations of a broad range of specimens of different sizes, shapes and compositions. The method does not require any extensive numerical modeling, relying only on the data provided by the magnetometer. The solution can be straightforwardly implemented in every field where magnetic investigations are of a prime importance, including the emerging new fields of topological insulators, 3D-Dirac semimetals and 2D-materials.

Spin flop and crystalline anisotropic magnetoresistance in CuMnAs

“…The SQUID measurements were performed on a 5.4 mm by 5.4 mm sample at 2 K using a Quantum Design MPMS system. To in situ compensate the much larger magnetic response of the GaP substrate, the sample was mounted between two abutting 8 cm long strips cut from another (equivalent) 2" GaP wafer, and careful calibration procedures were performed [34]. The compensational sample holder assembled for these measurements is presented in Fig.…”

Electrical characteristics of vertical-geometry Schottky junction to magnetic insulator (Ga,Mn)N heteroepitaxially grown on sapphire

“…The magnetic characterization has been performed using a Quantum Design MPMS XL Superconducting Quantum Interference Device (SQUID) magnetometer. Because of a low Mn content and a small thickness of the layer deposited on a bulky sapphire substrate, the accurate determination of magnetization as a function of temperature T and magnetic field H has required an extension of the previous experimental methodology [38][39] to an active, in situ, compensation of the dominating flux of the sapphire [40]. Figure 1 summarizes the main magnetic features of the layer studied here.…”

“…Prior to the TRM measurement the sample had been cooled down at 1 kOe to the base temperature and the field was quenched. The vanishing point of the TRM signal indicates the Curie transition temperature, here about 8 K. Inset: low field hystereses curves at 1.8 and 300 K. The magnetic flux of the sapphire substrate has been removed using in situ active compensation method[40].…”

Raman scattering studies of the lateral Mn distribution in MBE-grown Ga1-Mn N epilayers

“…The existence of the optimum value of T g for achieving the most efficient Mn incorporation in GaN at the given growth conditions employed by us (about 605 +/-5 °C) results in a situation that the central parts of samples S620 and S605 exhibit the highest, whereas the centre of S590 sample exhibits the lowest x found in each of these samples. The detailed in-depth magnetic studies, performed according to the lab-code [36] and tools [37] elaborated for studies of minute magnetic moments deposited on bulky substrates, established the single magnetic phase constitution of the studied layers [5].…”