Magnetization of magnetically inhomogeneous Sr2FeMoO6-δ nanoparticles

Magnetization is a key property of magnetic materials. Nevertheless, a satisfactory, analytical description of the temperature dependence of magnetization in double perovskites such as strontium ferromolybdate is still missing. In this work, we develop, for the very first time, a model of the magnetization of nanosized, magnetically inhomogeneous Sr2FeMoO6-δ nanoparticles. The temperature dependence of magnetization was approximated by an equation consisting of a Bloch-law spin wave term, a higher order spin wave correction, both taking into account the temperature dependence of the spin-wave stiffness, and a superparamagnetic term including the Langevin function. In the limit of pure ferromagnetic behavior, the model is applicable also to SFMO ceramics. In the vicinity of the Curie temperature (T/TC > 0.85), the model fails.

Download Full-text

Electrical characterisation of higher order spin wave modes in vortex-based magnetic tunnel junctions

Communications Physics ◽

10.1038/s42005-021-00614-3 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Alex. S. Jenkins ◽

Lara San Emeterio Alvarez ◽

Samh Memshawy ◽

Paolo Bortolotti ◽

Vincent Cros ◽

...

Keyword(s):

Spin Wave ◽

Tunnel Junctions ◽

Magnetic Tunnel Junctions ◽

Higher Order ◽

Spin Torque ◽

Micromagnetic Simulations ◽

Higher Order Modes ◽

Spin Diode ◽

Super High Frequency ◽

Wave Modes

AbstractNiFe-based vortex spin-torque nano-oscillators (STNO) have been shown to be rich dynamic systems which can operate as efficient frequency generators and detectors, but with a limitation in frequency determined by the gyrotropic frequency, typically sub-GHz. In this report, we present a detailed analysis of the nature of the higher order spin wave modes which exist in the Super High Frequency range (3–30 GHz). This is achieved via micromagnetic simulations and electrical characterisation in magnetic tunnel junctions, both directly via the spin-diode effect and indirectly via the measurement of the coupling with the gyrotropic critical current. The excitation mechanism and spatial profile of the modes are shown to have a complex dependence on the vortex core position. Additionally, the inter-mode coupling between the fundamental gyrotropic mode and the higher order modes is shown to reduce or enhance the effective damping depending upon the sense of propagation of the confined spin wave.

Download Full-text

Modeling of the Temperature Dependence of Soft Magnetic Materials

2020 IEEE Energy Conversion Congress and Exposition (ECCE) ◽

10.1109/ecce44975.2020.9235747 ◽

2020 ◽

Author(s):

Gereon Goldbeck ◽

Gerd Bramerdorfer ◽

Wolfgang Amrhein ◽

Josef Hinterdorfer ◽

Bernhard Weis

Keyword(s):

Temperature Dependence ◽

Magnetic Materials ◽

Soft Magnetic Materials ◽

Soft Magnetic

Download Full-text

A novel model for the interpretation of small-angle scattering experiments of self-affine structures

Journal of Applied Crystallography ◽

10.1107/s0021889809048791 ◽

2009 ◽

Vol 43 (1) ◽

pp. 12-16 ◽

Cited By ~ 6

Author(s):

Gerald J. Schneider ◽

D. Göritz

Keyword(s):

Small Angle ◽

Analytical Description ◽

Small Angle Scattering ◽

Filled Rubber ◽

Angle Scattering ◽

Affine Structures ◽

Novel Theory ◽

First Time ◽

Novel Model ◽

Solid Spheres

A novel theory is presented which allows, for the first time, the analytical description of small-angle scattering experiments on anisotropic shaped clusters of nanoparticles. Experimentally, silica-filled rubber which is deformed is used as an example. The silica can be modelled by solid spheres which form clusters. The experiments demonstrate that the clusters become anisotropic as a result of the deformation whereas the spheres are not affected. A comparison of the newly derived model function and the experiments provides, for the first time, microscopic evidence of the inhomogeneous deformation of clusters in the rubbery matrix.

Download Full-text

Temperature dependence of the spin wave in Co/CoO bilayers

Journal of Magnetism and Magnetic Materials ◽

10.1016/j.jmmm.2006.10.593 ◽

2007 ◽

Vol 310 (2) ◽

pp. e539-e540

Author(s):

H. Moradi

Keyword(s):

Temperature Dependence ◽

Spin Wave

Download Full-text

TRANSPORT CHARACTERISTICS IN c-AXIS La2-xSrxCuO4 (LSCO) SINGLE CRYSTALS

International Journal of Modern Physics B ◽

10.1142/s0217979205028785 ◽

2005 ◽

Vol 19 (01n03) ◽

pp. 447-450

Author(s):

SANG-JAE KIM ◽

TAKESHI HATANO

Keyword(s):

Temperature Dependence ◽

Single Crystals ◽

Critical Current ◽

Focused Ion Beam ◽

Ion Beam ◽

Etching Method ◽

First Time ◽

Small Voltage

c-axis micro-bridges of La 2-x Sr x CuO 4 ( LSCO ) single crystals were fabricated by the focused-ion-beam (FIB) etching method. Small rectangular LSCO pieces were fabricated by cutting and grinding single crystals of underdoped LSCO of x=0.09. The size of LSCO single crystals between electrodes was cut to 20×40μm2 in ab-plane by using the FIB etching method. Superconductor-insulator-superconductor (SIS) like-branch structures on I-V curves of the LSCO stacks were observed for the first time. The branch structures exhibited voltage jumps of several tens mV in the range of from 1.7 K to 5 K with temperature dependence. When the temperature is changed from 5 K to 1.7 K , the critical current and the next branch split into a few of small voltage jumps with the intervals of several mV in the range of from 0.1 mV and 2.0 mV .

Download Full-text

Dithiolium and diselenolium compounds of the transition metals

Australian Journal of Chemistry ◽

10.1071/ch9690083 ◽

1969 ◽

Vol 22 (1) ◽

pp. 83 ◽

Cited By ~ 33

Author(s):

RL Martin ◽

IM Stewart

Keyword(s):

Transition Metals ◽

Temperature Dependence ◽

Mössbauer Spectra ◽

Mossbauer Spectra ◽

First Time

The preparations are reported of an extended series of compounds of the type ML2X4 where M is Mn, Fe, Co, or Ni; X is Cl or Br; and L is analytically identical with dithioacetylacetone. �� Electronic, infrared, and Mossbauer spectra together with the temperature dependence of the magnetism (80-300�K) of these compounds establish-contrary to previous suggestions in the literature-that they should be properly formulated as tetrahalometallate salts of the 3,5- dimethyl-1,2-dithiolium cation. Simple salts of this cation (such as the iodide) have also been isolated. �� During the course of this work salts (I- and [CoCl4]2-) of the hitherto unknown 3,5-dimethyl-1,2-diselenolium ion were synthesized and characterized for the first time.

Download Full-text

Free Vibration of Moderately Thick Conical Shells Using a Higher Order Shear Deformable Theory

Journal of Vibration and Acoustics ◽

10.1115/1.4027862 ◽

2014 ◽

Vol 136 (5) ◽

Cited By ~ 7

Author(s):

R. D. Firouz-Abadi ◽

M. Rahmanian ◽

M. Amabili

Keyword(s):

Free Vibration ◽

Boundary Conditions ◽

Equations Of Motion ◽

Free Vibration Analysis ◽

Higher Order ◽

Arbitrary Boundary ◽

Conical Shells ◽

First Time ◽

Circumferential Wave ◽

Shear Deformable

The present study considers the free vibration analysis of moderately thick conical shells based on the Novozhilov theory. The higher order governing equations of motion and the associate boundary conditions are obtained for the first time. Using the Frobenius method, exact base solutions are obtained in the form of power series via general recursive relations which can be applied for any arbitrary boundary conditions. The obtained results are compared with the literature and very good agreement (up to 4%) is achieved. A comprehensive parametric study is performed to provide an insight into the variation of the natural frequencies with respect to thickness, semivertex angle, circumferential wave numbers for clamped (C), and simply supported (SS) boundary conditions.

Download Full-text