Resonant Magnetic X-ray Scattering with high magnetic fields on highly correlated electrons systems

• Grant number: 05/01128-4
• Support Opportunities: Scholarships abroad - New Frontiers
• Start date: September 19, 2005
• End date: September 18, 2006
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Carlos Manuel Giles Antunez de Mayolo
• Grantee: Carlos Manuel Giles Antunez de Mayolo
• Host Investigator: Luigi Paolasini
• Host Institution: Instituto de Física Gleb Wataghin (IFGW). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: European Synchrotron Radiation Facility (ESRF), France

Abstract

In this project X-ray magnetic scattering under high magnetic fields will be used to obtain crystallographic, magnetic and orbital ordering properties of rare-earth metals and new intermetallic compounds of the series of the new heavy fermions based on Ce and presenting unconventional superconductivity. The interest in this study is based in the interplay that charge distribution, orbital ordering and magnetic ordering have on the magnetic and transport properties of these systems. In particular in the heavy fermions compounds we are interested in the understanding on how the dimensionality of the system affects the non conventional superconductivity on Ce based systems of the type RmMnIn(3m+2n) (R = La - Tb; M = Rh, Ir). The study of these series in the cases when the rare-earth atom has a large absorption cross section for neutrons turns the X-ray scattering technique the only one capable of getting fundamental information about it. This project will be performed at the Magnetic Scattering Group of the ESRF but concerns also a large network of interactions mainly connected to the Group of Optical and Magnetic Properties (GPOM) of the IFGW, as well as collaborations with Los Alamos National Laboratory, Argonne National Laboratory and the European Synchrotron Radiation Facility itself. The synthesis of good quality single crystals as well as the main macroscopic characterizations involving transport, magnetic and macroscopic properties were performed at our institute IFGW/UNICAMP. X-ray magnetic scattering will be performed at the ID20 beamline of the ESRF. These measurements will complement preliminary results obtained at the XRD2 High Resolution X-ray Scattering Beamline at the LNLS (which was financed by FAPESP Young Scientist Program under contract 96/05586-6). The motivation of this project consists in the implementation of new instrumentation allowing the application of new X-ray scattering techniques based in the simultaneous measurement of the azimuthal dependence of the X-ray scattering cross section to the complete polarization determination opening the way to get important information on the microscopic magnetic properties as well as the possibility to study these systems under high applied magnetic fields. In addition to the capability of determining the wave-vector propagation vectors it will be possible to obtain the absolute magnetization amplitude and direction at each crystallographic site. All these techniques are very recent and new and presently do not exist in Brazil. (AU)