125 research outputs found
Forecasting Vehicle Mobility in Remote Areas -An Aid to Military Vehicle Design
Military vehicles are designed for off the road mobility. These are liable for deployment on varying ground conditions. Terrain parameters effecting vehicle systems design are listed. To avoid large scale measurement of terrain parameters, use of physiographic maps in forecasting these parameters has been suggested. Field tests to ascertain the similarity of soil strength parameter between the similar physiographic terrain units, called land facets were conducted and the tests confirmed the usefulness of the technique
Structural and ferromagnetic properties of an orthorhombic phase of MnBi stabilized with Rh additions
The article addresses the possibility of alloy elements in MnBi which may
modify the thermodynamic stability of the NiAs-type structure without
significantly degrading the magnetic properties. The addition of small amounts
of Rh and Mn provides an improvement in the thermal stability with some
degradation of the magnetic properties. The small amounts of Rh and Mn
additions in MnBi stabilize an orthorhombic phase whose structural and magnetic
properties are closely related to the ones of the previously reported
high-temperature phase of MnBi (HT~MnBi). To date, the properties of the
HT~MnBi, which is stable between and ~K, have not been studied in
detail because of its transformation to the stable low-temperature MnBi
(LT~MnBi), making measurements near and below its Curie temperature difficult.
The Rh-stabilized MnBi with chemical formula MnRhBi
[] adopts a new superstructure of the NiAs/NiIn structure
family. It is ferromagnetic below a Curie temperature of ~K. The critical
exponents of the ferromagnetic transition are not of the mean-field type but
are closer to those associated with the Ising model in three dimensions. The
magnetic anisotropy is uniaxial; the anisotropy energy is rather large, and it
does not increase when raising the temperature, contrary to what happens in
LT~MnBi. The saturation magnetization is approximately ~/f.u. at low
temperatures. While this exact composition may not be application ready, it
does show that alloying is a viable route to modifying the stability of this
class of rare-earth-free magnet alloys.Comment: 9 pages, 10 figure
Origin of the spin reorientation transitions in (FeCo)B alloys
Low-temperature measurements of the magnetocrystalline anisotropy energy
in (FeCo)B alloys are reported, and the origin of this
anisotropy is elucidated using a first-principles electronic structure
analysis. The calculated concentration dependence with a maximum near
and a minimum near is in excellent agreement with experiment.
This dependence is traced down to spin-orbital selection rules and the filling
of electronic bands with increasing electronic concentration. At the optimal Co
concentration, depends strongly on the tetragonality and doubles under a
modest 3% increase of the ratio, suggesting that the magnetocrystalline
anisotropy can be further enhanced using epitaxial or chemical strain.Comment: 4 pages + supplementary material, 6 figures. Accepted in Applied
Physics Letter
Study of the ferromagnetic quantum phase transition in Ce3−xMgxCo9
The Ce (Formula presented.) Mg (Formula presented.) Co (Formula presented.) system evolves from a Pauli paramagnetic ground state for x = 0 to a ferromagnetic ground state for (Formula presented.) in single-phase, polycrystalline samples [Lamichhane, V. Taufour, A. Palasyuk, Q. Lin, S.L. Budko, and P.C. Canfield, (Formula presented.) : transformation of a Pauli paramagnet into a strong permanent magnet, Phys. Rev. Appl. 9 (2018), p. 024023]. In order to better understand this behaviour, single-crystalline samples of Ce (Formula presented.) Mg (Formula presented.) Co (Formula presented.) for x = 0.01, 0.16, 0.24, 0.35, 0.43 and 0.50 were grown using the flux growth technique, and electrical transport and magnetic properties were studied. The (Formula presented.) -x phase diagram we infer shows that the system has a quantum phase transition near x = 0.35, transforming to a ferromagnetic ground state
- …