scholarly journals Nuclear Orientation as a Tool for Investigation of Magnetic Multilayers with Rare Earths

1998 ◽  
Vol 51 (2) ◽  
pp. 255 ◽  
Author(s):  
Milos Trhlík ◽  
Milos Rotter ◽  
Nathal Severijns ◽  
Ludo Vanneste
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Magnetic Moment ◽  
Nuclear Orientation ◽  
Magnetic Moments ◽  
Perpendicular Magnetic Anisotropy ◽  
Exchange Interactions ◽  
Magnetic Multilayers ◽  
Crystalline Anisotropy ◽  
Low Dimensional

Low-temperature nuclear orientation (NO) is presented as a useful tool to study the behaviour of rare earth (RE) ionic magnetic moments in magnetic multilayers. NO is shown to give rather direct information about the direction of RE ionic moments in such low-dimensional systems. In particular, the perpendicular magnetic anisotropy (PMA) can be directly monitored using RE atoms as probes. The potential of NO is demonstrated by our recent results, which concern the Fe/Tb multilayers. We have studied NO of 160Tb in Fe(40 Å)/Tb(x Å) (x = 5–30) and found that the Tb magnetic moments show PMA at low external magnetic fields (Bext). PMA of the Tb spins is found to be more pronounced when the Tb layer is thinner. It was found that Bext has a complicated influence on the Tb magnetic moment misalignment, which is connected with an interplay between PMA, the exchange interactions and the shape and magnetic crystalline anisotropy.

XMCD study of the induced magnetic moment in non-magnetic Ga and Ge atoms in intermetallic compounds

2011 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
R. Boada ◽  
C. Piquer ◽  
M. A. Laguna-Marco ◽  
J. Chaboy
Keyword(s):  
Electronic Structure ◽  
Rare Earth ◽  
Magnetic Moment ◽  
Magnetic Moments ◽  
Exchange Interactions ◽  
Magnetic Polarization ◽  
The Past ◽  
Orbital Magnetism ◽  
Insight Into ◽  
Laves Phase Compounds

In the past few years, we have witnessed the appearance of exotic magnetism of atoms in nano-scaled systems associated with compounds that are non-magnetic in their bulk form. Different models ranging from orbital magnetism delocalized over the whole molecule to localized one associated to the modification of the electronic structure have been proposed. Hence, one of the main challenges is to determine the mechanism that induces both the magnetic moment and the exchange interactions, leading to the ferromagnetic-like behaviour in these nanostructures. Aimed at obtaining a deeper insight into the induction of magnetic moments on nominally non-magnetic atoms, we have performed an XMCD study on rare-earth–iron Laves phase compounds containing Ga or Ge. XMCD probes the magnetic polarization of both Ga and Ge in these compounds. Our results show that when the rare-earth (R) is non-magnetic this polarization is uniquely due to the hybridization with the Fe neighbours, while it is enhanced when R is magnetic due to the Fe–R hybridization. As a consequence, the magnetic polarization of both Ge and Ga atoms differs as this hybridization does.

Rare Earth-Transition Metal Indides with Lu5Ni2In4-type Structure

2008 ◽  
Vol 63 (12) ◽  
pp. 1447-1449 ◽  
Author(s):  
Roman Zaremba ◽  
Wilfried Hermes ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Powder Diffraction ◽  
Magnetic Moment ◽  
Magnetic Moments ◽  
Type Structure ◽  
Induction Melting ◽  
X Ray ◽  
Arc Melting ◽  
Experimental Magnetic Moment

New intermetallic compounds RE5T2In4 (RE = Sc, Y, La-Nd, Sm, Gd-Tm, Lu; T = Rh, Ir) were synthesized by arc-melting of the elements or by induction melting of the elements in tantalum crucibles under flowing argon. The samples were characterized by X-ray powder diffraction. They crystallize with the orthorhombic Lu5Ni2In4-type structure, space group Pbam, Z = 2, a 2 : 1 intergrowth variant of CsCl and AlB2 related slabs of compositions InRE8 (distorted cubes) and RhRE6 (distorted trigonal prisms). Susceptibility measurements of Ce5Ir2In4 have revealed modified Curie- Weiss behavior above 70 K with an experimental magnetic moment of 2.45(1) μB / Ce atom. The cerium magnetic moments order ferri- or ferromagnetically at TC = 7.1(2) K.

Magnetic behaviour of synthetic Co2SiO4

2009 ◽  
Vol 65 (6) ◽  
pp. 664-675 ◽  
Author(s):  
Andrew Sazonov ◽  
Martin Meven ◽  
Vladimir Hutanu ◽  
Gernot Heger ◽  
Thomas Hansen ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Magnetic Structure ◽  
Magnetic Moment ◽  
Mirror Symmetry ◽  
Magnetic Moments ◽  
Exchange Interactions ◽  
Magnetic Behaviour ◽  
Relative Strength ◽  
Antiferromagnetic Ordering ◽  
Polarized Neutron

Synthetic Co2SiO4 crystallizes in the olivine structure (space group Pnma) with two crystallographically non-equivalent Co positions and shows antiferromagnetic ordering below 50 K. We have investigated the temperature variation of the Co2SiO4 magnetic structure by means of non-polarized and polarized neutron diffraction for single crystals. Measurements with non-polarized neutrons were made at 2.5 K (below T N), whereas polarized neutron diffraction experiments were carried out at 70 and 150 K (above T N) in an external magnetic field of 7 T parallel to the b axis. Additional accurate non-polarized powder diffraction studies were performed in a broad temperature range from 5 to 500 K with small temperature increments. Detailed symmetry analysis of the Co2SiO4 magnetic structure shows that it corresponds to the magnetic (Shubnikov) group Pnma, which allows the antiferromagnetic configuration (Gx , Cy , Az ) for the 4a site with inversion symmetry \bar{1} (Co1 position) and (0,Cy ,0) for the 4c site with mirror symmetry m (Co2 position). The temperature dependence of the Co1 and Co2 magnetic moments obtained from neutron diffraction experiments was fitted in a modified molecular-field model. The polarized neutron study of the magnetization induced by an applied field shows a non-negligible amount of magnetic moment on the oxygen positions, indicating a delocalization of the magnetic moment from Co towards neighbouring O owing to superexchange coupling. The relative strength of the exchange interactions is discussed based on the non-polarized and polarized neutron data.

XV.—Low Temperature Experiments in Magnetism

1909 ◽  
Vol 29 ◽  
pp. 287-294
Author(s):  
James G. Gray ◽  
Hugh Higgins
Keyword(s):  
Low Temperature ◽  
Air Temperature ◽  
Magnetic Moment ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Metals And Alloys ◽  
Considerable Reduction

The alterations brought about in the magnetic moments of magnets, composed of various metals and alloys, by alternate cooling and warming between ordinary room temperature and that of liquid air have been very fully investigated by Dewar and Fleming. It was found by these experimenters that in the case of most of the metals examined the effect of the first cooling upon the magnet—which had previously been magnetised to saturation in the field of an electromagnet—was to bring about a very considerable reduction in its magnetic moment. On allowing the magnet to warm to room temperature its magnetic moment still further diminished. On cooling once more to the liquid air temperature the magnetic moment increased, and from and after this stage it was found that the magnetic moment of the magnet when cold exceeded that of the magnet when at room temperature by a definite amount. The changes brought about by the treatment were found to be much greater in the annealed than in the quenched condition of the material.

Finite Size Effects in Magnetic Multilayers Induced by Interaction with the Substrate

2015 ◽  
Vol 233-234 ◽  
pp. 43-46
Author(s):  
M.V. Kostyuchenko
Keyword(s):  
Magnetic Moment ◽  
Uniaxial Anisotropy ◽  
Finite Size ◽  
Exchange Interactions ◽  
Magnetic Multilayers ◽  
Analytical Investigation ◽  
Finite Size Effects ◽  
Finite Difference Equations ◽  
Magnetic Layers ◽  
Significant Difference

The technique of finite difference equations is used for analytical investigation of magnetization pattern in magnetic multilayers. The magnetic multilayers with equal magnetic layers and ferrimagnetic multilayers are considered. Heisenberg and biquadratic exchange interactions and uniaxial anisotropy are taken into account. The analytical dependencies of total magnetic moment on external magnetic field are obtained taking into account the strong interaction with the substrate. The significant difference in the behavior of magnetic moment is derived for ferrimagnetic multilayers with odd and even layers number.

Study of perpendicular induced magnetic moments in the Ag of Ag/Fe multilayers

1997 ◽  
Vol 475 ◽  
Author(s):  
T. Phale ◽  
J. Dekoster ◽  
P. De Moor ◽  
P. Schuurmans ◽  
N. Severijns ◽  
...  
Keyword(s):  
Low Temperature ◽  
Magnetic Fields ◽  
Nuclear Orientation ◽  
Magnetic Moments ◽  
Magnetic Behaviour

AbstractWe investigated the induced magnetic behaviour of the Ag of Fe/Ag multilayers with low temperature nuclear orientation. The experiments show induced magnetic moments in all samples. Furthermore, multilayers with 2ML and 4ML of Ag, these moments do not lie in the plane of the multilayer at low external magnetic fields.

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