Intrinsic magnetic properties of single-phase Mn1+xGa (0 < x < 1) alloys

Abstract

Magnetization measurements have been carried out on a series of carefully prepared single-phase Mn1 + xGa (0 < x < 1) alloys. The saturation magnetization Ms, measured at 5 K, has a value of 92.0 emu/g for x = 0.15. This is the highest value reported in these alloys and is close to the calculated value of 116 emu/g for the stoichiometric compound (x = 0). Ms decreases gradually with x and has a value of 60.7 emu/g for x = 0.86. This behavior is consistent with the extra Mn atoms occupying Ga sites and coupling antiferromagnetically with the rest of the Mn atoms. The intrinsic magnetic properties of the Mn-Ga alloys indicate their great potential as novel, rare-earth free permanent magnetic materials.

Properties of Thin Film-Covered GaN(0001) Surfaces

“…They are rotated at 60° relative to each other. The achieved lattice parameter is in line with the structure of the single-phase Mn1+xGa (0 < x < 1) alloys for which the lattice constant is around 3.88 Å [89], clearly demonstrating the formation of alloys on the surface. XPS and UPS provide information on the physicochemical properties of the annealed system.…”

The Impact of the Composition Effect on Ferromagnetic Properties of Tb2Co2Ga

“…Such a composition effect is actually observed [8] in Nd 3 Pd 20 Ge 6 , which shows a slight decrease of the Néel temperature as the Pd atomic composition is increased from 19.2 to 21. Another example is Mn 1+x Ga, which is a ferromagnet showing a reduced T C with decreasing Mn concentration [9]. The study that found this effect presented a detailed composition effect of ferromagnetic properties that depend on the crystal structure parameters.…”

The Magnetic and Crystal Structure of MnxGa (1.15 ≤ x ≤ 1.8) Alloys

“…The as-cast ingots were annealed in a tubular vacuum furnace at temperatures, T a , ranging from 700 K to 900 K for one to seven days and then quenched into ice water. The annealing step is crucial for obtaining single-phase alloys, and the optimal annealing temperature range was found to be quite narrow and depended critically on the composition of the alloy 3 .…”

“…Therefore, we turn to neutron diffraction where there is almost optimal contrast between Mn and Ga (coherent scattering lengths, b c , are: b c (Mn) = −3.75 fm and b c (Ga) = +7.288 fm), and we are also sensitive to the magnetic ordering. This latter sensitivity is important as the magnetisation of Mn x Ga decreases with increasing x 3 , suggesting that the additional Mn couples antiferromagnetically (AF) to the ferromagnetic (FM) Mn found in the parent MnGa cell.…”

“…In a previous paper we described the excellent intrinsic magnetic properties of the Mn x Ga system 3 . Here we concentrate on establishing the basic crystal and magnetic structures; determining the location and ordering behaviour of the excess manganese.…”