"

Cookies ussage consent

Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.

I agree, do not show this message again.

Inelastic neutron scattering study of spin gap formation in heavy fermion compounds

D. T. ADROJA1,* , K.A. MCEWEN2, J.-G. PARK3, A.D. HILLIER1, N. TAKEDA4, P. S. RISEBOROUGH5, T. TAKABATAKE6

Affiliation

  1. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, UK
  2. Department of Physics and Astronomy, and London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK
  3. Department of Physics, SungKyunKwan University, Suwon 440-746, Korea and Center for Strongly Correlated Materials Research, Seoul National University, Seoul 151-747, Korea
  4. Faculty of Engineering, Niigata University, Niigata, 950-2181, Japan
  5. Department of Physics, Temple University, Barton Hall, 1900N. 13th Street, Philadelphia, PA 19122, USA
  6. Department of Quantum Matter, ADSM, Hiroshima University, Kagamiyama 1-3-1, Higashi Hiroshima 739-8530, Japan

Abstract

According to conventional theories of strongly correlated electron systems, the natural consequence of strong hybridization between f-electrons and conduction electrons is the opening of a gap in both charge and spin channels. Despite their importance, there are few experimental observations of such gaps in real materials. Recently the charge gap in d- and felectron systems has been investigated using optical studies. However, due to the q=0 limitation of the technique, optical studies cannot give information on the wave vector dependence of the gap. Inelastic neutron scattering is a unique technique and provides direct information on the spin gap energy as well as its wave vector and temperature dependence. Further, knowledge of the wave vector dependence of the gap, in particular the spin gap, provides important information about the microscopic mechanism of the gap formation. Recently we have investigated the spin gap formation, and its relation to the charge gap, in several Ce, Yb and U based compounds using inelastic neutron scattering techniques. We review here the nature of the spin gap in CeT4Sb12 (T = Ru, Os and Fe), CeRhAs and U2-xThxRu2Sn compounds based on our recent neutron scattering studies. We compare the magnitude of the spin gaps we have measured in this way with that of the charge gaps measured in optical studies. We have found a universal scaling relation between the spin gap energy and the Kondo temperature (TK) for many strongly correlated electron systems and the results are discussed..

Keywords

Spin gap formation, Inelastic neutron scattering investigations, Mixed-valence behaviour, Rare earth and actinide based intermetallic compounds.

Submitted at: April 1, 2008
Accepted at: July 1, 2008

Citation

D. T. ADROJA, K.A. MCEWEN, J.-G. PARK, A.D. HILLIER, N. TAKEDA, P. S. RISEBOROUGH, T. TAKABATAKE, Inelastic neutron scattering study of spin gap formation in heavy fermion compounds, Journal of Optoelectronics and Advanced Materials Vol. 10, Iss. 7, pp. 1564-1582 (2008)