Suppression of incommensurate spin-density waves in thin epitaxial Cr(110) layers of a V/Cr multilayer

We observed a complete suppression of the incommensurate spin-density wave in thin Cr layers of a V/Cr multilayer in a temperature range from 550 K down to 2 K. The (110)-oriented V/Cr multilayer consisting of 30 nm thick Cr layers and 5 nm thick V layers was investigated by neutron and X-ray diffraction (XRD). From the XRD experiments we were able to determine that the epitaxial strain of the Cr layers in the V/Cr multilayer is about 90% larger than in earlier studied Fe/Cr(110) multilayers. That leads to a completely different magnetic phase diagram as revealed by neutron diffraction experiments. The existence of the commensurate antiferromagnetic structure in the Cr layers can be observed in the whole temperature range without a phase transition to an incommensurate spin-density wave at lower temperatures. In order to elucidate the proximity effects further we also performed experiments in an external magnetic field. Up to a field of 4 T we found no change in the magnetic structure of the Cr films whereas in earlier experiments on Fe/Cr(110) multilayers we could observe a strong perpendicular pinning of the Cr polarization to the Fe magnetization.Received: 28 August 2003, Published online: 8 December 2003PACS: 75.30.Fv spin-density waves - 75.70.-i magnetic properties of thin films, surfaces, and interfaces - 61.12.-q Neutron diffraction and scattering     

Author Index for Volume 12

Authors Index

Author Index for Volume 12     

Mittlere Schwingungsamplituden,thermodynamische Funktionen und molekulare Polarisierbarkeiten von gemischten Phosphorhalogeniden des Typs PX2Y

Zusammenfassung Es werden verschiedene molekulare Konstanten der Phosphorverbindungen PF₂Cl, PCl₂F, PF₂Br, PBr₂F, PCl₂Br und PBr₂Cl berechnet. Mit Hilfe der Methode vonCyvin werden mittlere Schwingungsamplituden für Zimmertemperatur ermittelt. Die mittleren Amplituden des P–F-, P–Cl- und P–Br-Abstandes nehmen mit zunehmender Gruppenelektronegativität der Halogenatome 1/3X _i ab. Weiterhin werden thermodynamische Funktionen sowie molekulare Polarisierbarkeiten nach der Methode vonLippincott undStutman berechnet.     

Transition Metal Thiometalates: Properties and Significance in Complex and Bioinorganic Chemistry

In their highest oxidation states the early transition metals V, Nb, Ta, Mo, W, and Re form tetrahedral, strongly colored thioanions endowed with some remarkable properties. Thiometalates can be formed by solid-state reactions or in solution from the oxometalates. Poly-thiometalates with mixed valences can be produced by new types of intramolecular condensation-redox reactions from thioanions. The metal-sulfur bonds can react either nucleophilically or electrophilically, and in the case of the Mo–S bonds this is of biochemical interest. It is important to mention the applications of thiometalates as ligands in complex chemistry (generation of multi-metal complexes, versatile coordination behavior, unique electronic properties of the ligands), in which thiometalato complexes with a variety of electron populations can exist because of the marked electron delocalization. Apart from this, MoS has a significance in bioinorganic problems, e.g. the nitrogenase problem and Cu? Mo antagonism.