Study of magnetic anisotropy and magnetization reversal using the quadratic magnetooptical effect in epitaxial CoxMnyGez(111) films

We investigate the magneto-optical properties of a nonstoichiometric, epitaxial Co 2 Mn 0.77 Ge 0.42 ͑001͒ film grown on a MgO-buffered MgO͑001͒ single-crystal substrate. Magneto-optical Kerr effect magnetometry indicates that the sample has strong uniaxial anisotropy, whereas the easy and hard axes of magnetization are tilted by ϳ10°with respect to the ͓110͔ and ͓110͔ directions, respectively. A modest quadratic Kerr effect with an amplitude of 0.4 mdeg was observed. Brillouin light scattering spectroscopy was used to find that the exchange constant A, spin-wave stiffness D, and saturation magnetization M s are 22.5 pJ/m, 413 meV Å 2 , and 6.43 B / f.u., respectively. The saturation magnetization value suggests that the Slater-Pauling rule might apply to such nonstoichiometric compositions.

Section: -mentioning

confidence: 99%

Magneto-optical investigation of epitaxial nonstoichiometric Co2MnGe thin films

Trudel

Hamrle

Hillebrands

et al. 2010

“…Although to date the spin polarized behavior has not been confirmed, the possibility that deviations from stoichiometry could cause a reduction in spin polarization has motivated ternary mapping of the Co-Mn-Ge system. 105,132,133 The MOKE imaging technique was used to rapidly characterize the magnetic properties of the entire ternary system. Figure 35 shows the transverse differential MOKE intensity image of a 25 nm thick continuous ternary phase diagram chip measured using a charge couple display (CCD) camera while applying a magnetic field of þ/À5 KOe.…”

mentioning

confidence: 99%

Applications of high throughput (combinatorial) methodologies to electronic, magnetic, optical, and energy-related materials

Green

Takeuchi

Hattrick‐Simpers

2013

227

189

High throughput (combinatorial) materials science methodology is a relatively new research paradigm that offers the promise of rapid and efficient materials screening, optimization, and discovery. The paradigm started in the pharmaceutical industry but was rapidly adopted to accelerate materials research in a wide variety of areas. High throughput experiments are characterized by synthesis of a "library" sample that contains the materials variation of interest (typically composition), and rapid and localized measurement schemes that result in massive data sets. Because the data are collected at the same time on the same "library" sample, they can be highly uniform with respect to fixed processing parameters. This article critically reviews the literature pertaining to applications of combinatorial materials science for electronic, magnetic, optical, and energy-related materials. It is expected that high throughput methodologies will facilitate commercialization of novel materials for these critically important applications. Despite the overwhelming evidence presented in this paper that high throughput studies can effectively inform commercial practice, in our perception, it remains an underutilized research and development tool. Part of this perception may be due to the inaccessibility of proprietary industrial research and development practices, but clearly the initial cost and availability of high throughput laboratory equipment plays a role. Combinatorial materials science has traditionally been focused on materials discovery, screening, and optimization to combat the extremely high cost and long development times for new materials and their introduction into commerce. Going forward, combinatorial materials science will also be driven by other needs such as materials substitution and experimental verification of materials properties predicted by modeling and simulation, which have recently received much attention with the advent of the Materials Genome Initiative. Thus, the challenge for combinatorial methodology will be the effective coupling of synthesis, characterization and theory, and the ability to rapidly manage large amounts of data in a variety of formats. V C 2013 AIP Publishing LLC. [http://dx

“…Through the investigation of the magnetic, electronic, and structural properties of these materials, it has come to light that many Co-based Heusler compounds show strong second-order magneto-optical Kerr effects. 2 For example, this has recently been reported for Co 2 FeSi, 3 Co 2 MnSi, 4 Co 2 MnGe, [5][6][7] and Co 2 FeSi 0:5 Al 0:5 8 epitaxial thin films.…”

Section: Introductionmentioning

confidence: 68%

Quadratic magneto-optical Kerr effect in Co2MnSi

Wolf

Hamrle

Trudel

et al. 2011

Quadratic magneto-optical Kerr effects (QMOKE) are investigated in epitaxial Co 2 MnSi thin films as a function of the post-deposition annealing temperature. We determine the amplitude of the QMOKE signal for different annealing temperatures, which provide various degrees of L2 1 crystal ordering, as manifested by X-ray diffraction. We observe that QMOKE is significantly present only when the L2 1 ordering phase is also present, and that the QMOKE signal increases with the higher degree of L2 1 ordering. Additionally, we notice that the linear magneto-optical Kerr effect (LMOKE) decreases with higher annealing temperature. A comparison of the linear and quadratic MOKE contributions shows the amplitudes are of similar magnitude. From these results, we conclude that the presence of QMOKE is linked to the higher degree of L2 1 ordering in Co 2 MnSi.