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The B20 structure is capable of supporting a long-range antiferromagnetic static spin density wave, and for transition metal silicides and germanides it has previously been found that the N6el temperatures, high field magnetizations and magnetic propagation vectors q all suggest a dependence on an electron concentration parameter. This relationship has yet to be confirmed.The present measurements from mixed alloys in the series CrSi/FeSi, CrSi/MnSi, CrSi/CoSi. MnSi/CoSi and CrGe/FeGe have extended the electron concentration range previously covered and the results support the suggested dependence. The q values are practically independent of temperature and the CrGe/FeGe display high N6eI temperatures comparable with that of FeGe. IC_ 1998 Elsevier Science B.V. All rights reserved. Ke3~t'ords:Antiferromagnetism; Dzyaloshinskii-Moriya interaction; Magnetic coupling -antiferromagnetic; Magnetic transitions Metallic alloys with the B20 (P213) crystal structure which lacks inversion symmetry have been found to support an antiferromagnetic static spin density wave at low temperatures probably through the operation of a Dzyaloshinskii-Moriya-type interaction I-l]. The periods of the magnetic structures observed are generally long and small-angle neutron scattering is an ideal technique for studying such systems. The variations with composition of the N~el temperatures, high-field magnetisations and propagation vectors q have previously been studied for a few such alloys and the similar form of all these has suggested a dependence on d-electron band filling [1,2]. Such at relationship has not yet been finally established and we have therefore fabricated a wide range of polycrystalline intermetallic silicides and germanides which span the electron concentration ranges of interest. We report the results of magnetization and SANS measurements carried out at Salford and RISO. respectively.Alloys have been prepared by argon arc melting from the mixed series CrSi/FeSi, CrSi/MnSi, CrSi/CoSi, MnSi/CoSi and CrGe/FeGe. The alloys were remelted *Corresponding author. Tel.: ÷ 44 16I 745 5259; fax: + 44 I61 745 5197: e-mail: j.g.booth@physics.salford.ac.uk. four or five times to ensure homogenisation, crushed into powder form and heat-treated in sealed ampoules. The silicides were heat treated at 825C for 24 h, quenched into water, and subsequent X-ray analysis indicated the B20 crystal structure, The germanides showed a two-phase structure after such treatment and it was necessary to heat these at 500-'C for 1 week before quenching to produce single-phase alloys. Magnetization measurements in fields up to 12 T were carried out on the Manchester/Salford VSM over the range 4-300 K. The SANS measurements were performed in the neighbourhood of the N6el temperatures over the low q range up to 0.10 k.-i.Typical results for the magnetization measurements as a function of field for the alloy Mno.95Cr0.osSi exhibiting long-range antiferromagnetism are shown in Fig. 1. In the antiferromagnetic regime the magnetization increases linea...

The magnetic properties of a series of the intermetallic compound Mn5−xTxSi3 with T=3d transition metal Ti, V, Cr, and Ni have been examined as a function of the magnetic field (0–12 T) and temperature (2–300 K). The alloys have the same hexagonal D88 crystal structure as Mn5Si3 with very little change in lattice spacing. The magnetization measurements show that the substitutional elements produce a variety of effects, dramatically altering the field and temperature dependence of the AF1/AF2 and AF2/paramagnetic transitions. It is assumed that since the Mn–Mn distances in the parent alloy are all near critical values for instability the substitution on to Mn sites interferes significantly in the Mn–Mn interactions.