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Results for “MAGNETOSTRICTION”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Magnetostriction-driven ground-state stabilization in 2H perovskites

In this paper, the magnetic ground state of Sr 3 ARuO 6 , with A =(Li,Na), is studied using neutron diffraction, resonant x-ray scattering, and laboratory characterization measurements of high-quality crystals. Combining these results allows us to observe the onset of long-range magnetic order and distinguish the symmetrically allowed magnetic models, identifying in-plane antiferromagnetic moments and a small ferromagnetic component along the c axis. While the existence of magnetic domains masks the particular in-plane direction of the moments, it has been possible to elucidate the ground state using symmetry considerations. We find that due to the lack of local anisotropy, antisymmetric exchange interactions control the magnetic order, first through structural distortions that couple to in-plane antiferromagnetic moments and second through a high-order magnetoelastic coupling that lifts the degeneracy of the in-plane moments. Finally, the symmetry considerations used to rationalize the magnetic ground state are very general and will apply to many systems in this family, such as Ca 3 ARuO 6 , with A = (Li,Na), and Ca 3 LiOsO 6 whose magnetic ground states are still not completely understood.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

P13631-E002PF: Pulsed field magnetostriction of Ba 2 CoTeO 6

Ba 2 CoTeO 6 is an insulating material consisting of two magnetic subsystems referred as A and B build of S=1/2 spins. Subsystem A is considered to be a Heisenberg-like antiferromagnet (AFM) on a triangular lattice and subsystem B is a J 1 -J 2 Ising-like AFM on a honey-comb lattice. The magnetic phase transitions are observed at T N1 = 12 K and T N2 =3K for A and B respectively. The application of magnetic fields unveils a rich phase diagram that varies depending on the direction of the applied field for either H ll c or H perp c. To date the phase diagram has been investigated by means of specific heat measurement up to 9T and susceptibility measurements with a SQUID magnetometer up to 7T. Magnetization measured in pulsed magnetic fields up to 60T at 1.3K and 4.2K reveal several steps and plateaux occurring at varying critical fields depending on the crystallographic direction. Common to the magnetization parallel c and perpendicular c is the saturation above 40T.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Pulsed Field Magnetostriction and Metamagnetism in UPt3

Metamagnetism (MM) characterized by a sudden rise in the magnetization at a critical field is a well established phenomenon in the hexagonal system UPt 3 , first noted at H = 20 T nearly three decades ago. However recent detailed measurements of the nonlinear magnetic susceptibility has raised new questions. With a careful analysis of the existing data and utilizing a phenomenological single energy scale (SES) model developed in this context one of us (BSS) was able to show that there is a distinct possibility of a second MM transition at a higher field. Depending upon the parameters chosen in the model this transition is predicted to occur in the range of 60 T-100 T. Thus measurements of the magnetic and magnetoelastic properties of UPt 3 in the highest available fields is desirable.

36 MATERIALS SCIENCE↗