Analysis of selected properties of powdered compacts

Magnetic materials are large and specific group of materials with interesting properties and useful applications. Some of them have been known for many years, but many important materials have only been discovered in recent decades. It can be expected that many newly discovered materials with specific properties will soon be used in applications in which magnetic materials have been used for a long time, but their properties will be better. The development of new magnetic materials will certainly bring the possibility of their use in such applications in which they have not been used before. This paper contains the review of the results of research focused on the study of soft magnetic ferromagnetic materials. Specifically, they are materials of chemical composition Fe19Ni81 (called Permalloy) and Fe16Ni79Mo5 (called Supermalloy). These materials were prepared in the form of powders by the technique of the mechanical milling. Subsequently, these powders were compacted with aim to prepare a compacted material of the desired shape and size with excellent magnetic properties. This research was focused on the study of the structure and magnetic properties of massive magnetic materials prepared by the compaction of the powders in order to prepare soft magnetic material with excellent properties competing with the material used so far.

From Atomic Level to Large-Scale Monte Carlo Magnetic Simulations

This paper refers to Monte Carlo magnetic simulations for large-scale systems. We propose scaling rules to facilitate analysis of mesoscopic objects using a relatively small amount of system nodes. In our model, each node represents a volume defined by an enlargement factor. As a consequence of this approach, the parameters describing magnetic interactions on the atomic level should also be re-scaled, taking into account the detailed thermodynamic balance as well as energetic equivalence between the real and re-scaled systems. Accuracy and efficiency of the model have been depicted through analysis of the size effects of magnetic moment configuration for various characteristic objects. As shown, the proposed scaling rules, applied to the disorder-based cluster Monte Carlo algorithm, can be considered suitable tools for designing new magnetic materials and a way to include low-level or first principle calculations in finite element Monte Carlo magnetic simulations.

Магнитострикция пленок граната (YSmLuCa)-=SUB=-3-=/SUB=-(FeGa)-=SUB=-5-=/SUB=-O-=SUB=-12-=/SUB=- методом низкочастотной восприимчивости

Certification of new magnetic materials requires high-precision nondestructive methods. The method of measuring the magnetostriction constant of films by studying low-frequency magnetic susceptibility at elastic deformation of the films is proposed. The method allows a tenfold improvement of the accuracy of measurements of the magnetostriction constant as compared with the methods applied earlier.

Ferromagnetic Oxime-Based Manganese(III) Single-Molecule Magnets with Dimethylformamide and Pyridine as Terminal Ligands

Two new members of the [Mn6] family of single-molecule magnets (SMMs) of formulae [Mn6(μ3-O)2(H2N-sao)6(dmf)8](ClO4)2 (1) and [Mn6(μ3-O)2(H2N-sao)6(py)6(EtOH)2][ReO4]2·4EtOH (2), (dmf = N,N′-dimethylformamide, py = pyridine, H2N-saoH2 = salicylamidoxime) have been synthesized and characterized structurally and magnetically. Both compounds were straightforwardly prepared from the deprotonation of the H2N-saoH2 ligand in the presence of the desired manganese salt and solvent (dmf (1) vs. py (2)). Compound 1 crystallizes in the triclinic system with space group Pī and 2 crystallizes in the monoclinic system with space group P21/n. In the crystal packing of 1 and 2, the (ClO4)− (1) and [ReO4]− (2) anions sit between the cationic [Mn6]2+ units, which are H-bonded to –NH2 groups from the salicylamidoxime ligands. The study of the magnetic properties of 1 and 2 revealed ferromagnetic coupling between the MnIII metal ions and the occurrence of slow relaxation of the magnetization, which is a typical feature of single-molecule magnet behavior. The cationic nature of these [Mn6]2+ species suggests that they could be used as suitable building blocks for preparing new magnetic materials exhibiting additional functionalities.