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Single crystal of the stoichiometric Ni2MnSn alloy (cubic L21 crystal structure) was prepared by the Czochralski method. The values of the magneto-crystalline anisotropy constant K1 have been determined at temperature 10 K under ambient and high hydrostatic pressures, K1 = + 0.17 × 104 and +1.96 × 104 J/m3 (0.7 GPa), respectively. The pressure-induced decrease of magnetization was confirmed and hence the significant non-trivial increase of uniaxial anisotropy with increasing pressure points to a possible distortion of the cubic structure of the single crystal under hydrostatic pressure. Simultaneously, the more pronounced and pressure almost insensitive magneto-crystalline anisotropy, K1 = + 9.1 × 104 J/m3, has been observed in the martensite phase (orthorhombic structure) of the off-stoichiometric Ni2Mn1.43Sn0.57 alloy. The effect of a directional dependence of the Young modulus that was theoretically derived in the case of the Ni2MnSn-based alloys is discussed. [ABSTRACT FROM AUTHOR]

Magnetization isotherms of the Fe64Ni36Invar alloy have been measured under pressure up to 5.3 GPa in magnetic field up to 5 T using a diamond anvil cell and SQUID magnetometer. The unambiguous change of the pressure parameter dlnMS/dP(from −9 to −13×10−2 GPa−1) has been observed in a narrow pressure interval from 2.5 to 3.5 GPa at all temperatures in the range from 5 to 300 K. The pressure interval, where the sharp decrease in magnetization was observed, coincides with the critical pressures of the pressure-induced decrease in Fe-moment that were determined by the X-ray Magnetic Circular Dichroism and the X-ray Emission Spectra studies, recently. The pronounced decrease in the Curie temperature of the Fe64Ni36alloy under pressure, dTC/dP= −44 ±2 K/GPa, has been confirmed. [ABSTRACT FROM AUTHOR]

In this communication, we compare effects of hydrostatic and chemical pressure on the magnetic properties of La0.67Ca0.33(CoxMn1-x)O3 ceramics. For ceramics with x=0.03, the Curie temperature TC increases under hydrostatic pressure with a slope d Tc/d p=+23.4 K/GPa. The saturated magnetization μs does not change with applied hydrostatic pressure. Chemical pressure was induced by substitution of Co for Mn. The substitution from x=0.03 to x=0.1 reduces the volume of the elementary cell by about 0.28%, but TC decreases from 203.4 to 167 K. The saturated magnetization μs is not affected by this substitution. [ABSTRACT FROM AUTHOR]

The magnetic properties of Y0.6Th0.4Co4B are studied to characterize the magnetic behaviour of the Co sublattice. Assuming that Y or Th has no effect on magnetic properties, one can think this behaviour to remain unchanged in all RCo4B compounds, where R is a non-magnetic element. However, it has been found that YCo4B and ThCo4B have different magnetic properties. Substituting Th for Y in YCo4B induces a decrease in the Curie temperature (from 378(2) to 302(2) K) and a decrease in the saturation magnetization (from 3.0(1) to 1.5(1) μB). Both the change of chemical pressure effect (due to the change of cell volume) and the change of valence could explain this behaviour. In order to isolate the effect of pressure, we synthesized the intermediate substituted compound Y0.6Th0.4Co4B and studied the evolution of its magnetic properties under hydrostatic pressure. We found the sensitivity of the Curie temperature to be dTC/dP=-0.7(2) K/kbar. The results strongly support the dominant effect of valence electrons on the magnetic properties of the Y0.6Th0.4Co4B intermetallic compound. [ABSTRACT FROM AUTHOR]

Abstract: The experimental study of the pressure effect on magnetization and compensation temperature of ferrimagnetic GdCo2Fe2B in a magnetic field up to 7 T under hydrostatic pressures up to 10 kbar is presented. Due to the mutual antiparallel arrangement of Gd and 3d sublattices and the negligible pressure effect on localized Gd magnetic moment, the observed increase of with pressure can be attributed to the pressure induced decrease of 3d magnetic moments, predominately to the decrease of Fe moment, . The pressure induced increase of is also responsible for the remarkable increase of under pressure . This opens the field to tunablibilty of the . [ABSTRACT FROM AUTHOR]

Abstract: The effect of pressure on magnetic properties of YCo12B6 and CeCo12B6 was studied in temperature range 5–300K at pressures up to 9kbar. The Curie temperature T C and spontaneous magnetization M S decrease with pressure for both compounds. The decrease can be attributed mostly to the volume dependence of both, the Co magnetic moment and the exchange interactions. The hybridization of the p–d states as a consequence of small distances between the Co and B atoms can be one reason of the relatively low pressure effects (ΔT C/Δp=−0.39±0.02K/kbar, dln M S/dp=−0.0013±0.0002kbar−1) in YCo12B6. Higher volume sensitivity of magnetic properties of CeCo12B6 in comparison with YCo12B6 can be attributed to the pressure induced changes of the Ce f- and Co d-states. [Copyright &y& Elsevier]

Abstract: Si substitution in YCo5 compound results in a dramatic reduction of both the Curie temperature and Co magnetic moments. The magnetic properties of the YCo4Si compound have been investigated at ambient and high pressures. YCo4Si is ferromagnetic with a Curie temperature of 320K only and a significantly reduced magnetization in comparison with YCo5. The logarithmic pressure derivative of saturation magnetization M S can be estimated dln M S/dp=(−3.0±0.5)×10−3 kbar−1. The effect of pressure on the Curie temperature has been investigated up to 12kbar. The Curie temperature, determined from thermomagnetic measurements in a low field (0.01T), is also found to be sensitive to the applied pressure dln T c/dp=(−1.25±0.5)×10−3 kbar−1. It is found that the large reduction of the magnetic properties is due to both a chemical and a pressure effect of the Si for Co substitution. [Copyright &y& Elsevier]

We report a study of the effect of hydrostatic pressure on the magnetocaloric effect in a La0.69Ca0.31MnO3 single crystal. The single crystal exhibits a much larger magnetic entropy change (ΔSm) than the corresponding polycrystalline samples, reaching 5.2 J/kg K and 8.5 J/kg K for a magnetic field variation of 1 T and 5 T, respectively. Under hydrostatic pressure, the peak position of ΔSm significantly moves to higher temperatures due to the shift of the magnetic phase transition, from 213.5 K under ambient pressure up to 236.5 K under a pressure of 1.1 GPa, while the maximum value of ΔSm remains nearly the same. These exceptional results demonstrate that the magnetocaloric effect in magnetic materials with strong spin-lattice coupling can be effectively tuned by pressure. [ABSTRACT FROM AUTHOR]

Presents an abstract of the study 'Pressure Effect on the Resistivity in GMR La[sub0.60]Y[sub0.07]Ca[sub0.33]MnO[sub3] Compound,' by Z. Arnold, K. Kamenev, M.R. Ibarra, P.A. Algarabel, C. Marquina, J. Blasco and J. Garcia.

The effect of external hydrostatic pressure on magnetic properties is studied for the UCo 0.995 Os 0.005 Al single crystal. At ambient pressure, the ground state is ferromagnetic. Even lowest applied pressure 0.11 GPa is sufficient to suppress ferromagnetism. A sharp metamagnetic transition is observed only in magnetic fields along the c axis of the crystal, similar to previously studied itinerant electron metamagnet UCoAl. Temperature dependence of the susceptibility for various pressures shows a broad maximum at T max ~ 20 K. The experimental data are analyzed with the theory of itinerant electron metamagnetism, which considers anisotropic thermal fluctuations of the uranium magnetic moment. The observed pressure dependence of the susceptibility at T max and the temperature for the disappearance of the first-order metamagnetic transition are explained with the theory. [ABSTRACT FROM AUTHOR]

Abstract: The pronounced magnetocaloric properties of Ni2± x Mn1± y Ga1± z alloys are strongly dependent on both the composition and the inter-atomic distances. Moreover, the off-stoichiometric Mn- and Ni-rich Ni2MnGa compounds exhibit mutually different magnetocaloric behaviour under high hydrostatic pressure. A pressure-induced co-occurrence of martensitic transformation and magnetic transition was found for Mn-rich compounds, resulting in a substantial increase of magnetocaloric effect. In contrast to this, the magnetocaloric effect was partially suppressed in the Ni-rich compounds under high pressure. These results reflect the specific role of Ni in the martensitic transformation of Ni2MnGa alloys. [Copyright &y& Elsevier]

Abstract: We studied the effect of hydrostatic pressure on the magnetic and magnetocaloric properties of the potential magnetic-refrigerant materials MnFeP1− x As x with x=0.35 and 0.55. While applied pressure reduces both the Curie temperature and magnetic moment of the former compound, the Curie temperature of the latter is increased whereas the moment is hardly affected by pressure. The same trends are seen in the magnetocaloric properties. These results indicate a different character of the magnetism in these two materials. While the compound with x=0.35 exhibits a volume instability like a weak itinerant ferromagnet, whereas the one with x=0.55 behaves as a strong itinerant ferromagnet. An alternative scenario may be formulated within the localized-moment picture. One may interpret the effect of pressure on the compound with x=0.35 as an indication of pressure-induced enhancement of antiferromagnetic interactions. This latter interpretation is offered by a pronounced enhancement of the high-field susceptibility under pressure. [Copyright &y& Elsevier]