Muon Spin Rotation and Relaxation
In µSR spectroscopy muons are implanted in a sample and come to rest
at interstitial sites. With measurement methods of nuclear physics one
can follow the Larmor precession of the muons. This allows conclusions on
internal magnetic fields in solids and their distribution and dynamics.
This animation shows the decay of a muon (re-animate by reloading this page) und
the angular distribution of the emitted positron at maximum (a=1) and mean
energy (a=1/3). It was kindly made available by
Macrae. The principle of µSR is based on the parity violation
in the decay of pions and muons. First this gives us spin polarised muons, and
second it correlates the emission direction of the decay positrons with the
direction of the muon spin at the time of the decay. Given these facts the muon becomes
a very sensitive probe for magnetic fields in matter. In muon spin rotation
the precession of the implanted muons in an external transverse magnetic field
In muon spin relaxation, on the other hand, one observes the decrease
of the muon polarisation without an external field or in longitudinal fields. A
comprehensive description of the µSR method can be found in the
of Ernst Schreier (in German).
µSR measurements can only be performed at suitable facilities of so-called
meson factories. We conduct our experiments at the following
The temperature range for experiments at the facilities there is
0.01 K to 1000 K. This is a selection of online available manuals for the
Informationen on µSR and the facilities can also be found on the pages
of other µSR groups.
Our research group uses µSR spectroscopy mainly in the study of the formation
of magnetism in the elements and compound of the rare earths (4f transition metals).
The research focuses on new materials like systems with heavy fermions,
in which, for example, superconductivity and magnetism can coexist, or so-called
Kondo metals, in which a strong competition prevails between the exchange interaction that
produced magnetism and the Kondo coupling that suppresses it. These materials form a
subgroup of the electronically highly correlated materials which include, among others,
the high temperature superconductors. In cooperation with other research groups,
complementary measurements are undertaken
like specific heat, susceptibility and neutron diffraction measurements.
Other research areas to which µSR is applied in the institute E15 include
the study of spin glasses and the magnetic behaviour of oxidic spinels.
Diploma theses and Ph.D. theses
- Eve Martin,
"Magnetische Eigenschaften des frustrierten Systems GdMn2,"
diploma thesis, 1997.
- Stefan Henneberger,
"Kritische Dynamik von uniaxialen und dipolaren Ferromagneten oberhalb
der kritischen Temperatur am Beispiel Gadolinium,"
Ph.D. thesis, 1996.
- Susanne Flaschin,
"Einfluß von Cu-Dotierung auf den nichtmagnetischen Grundzustand des Kondohalbleiters
CeNiSn - Eine µSR-Untersuchung,"
diploma thesis, 1995
- Franz-Josef Burghart,
"Bestimmung des Myonenortes in CePtSn,"
diploma thesis, 1994
- Claus Schopf,
"µSR-Messungen an Uranverbindungen mit AuCu3-Struktur,"
diploma thesis, 1994
- Ernst Schreier,
"Hochdruck-µSR-Experimente am Seltenen-Erd-Metall Gadolinium,"
diploma thesis, 1994
(complete HTML version in German).
- Klaus Mutzbauer,
"µSR-Messungen an Gd unter hohem Druck,"
diploma thesis, 1993
- Karl-Heinz Münch,
"Entwicklung eines analogen Meßverfahrens für
µSR-Spektroskopie mit hohen Ereignisraten,"
Ph.D. thesis, 1992
- Markus Weber,
"Lokale magnetische Eigenschaften von YMn2 unter besonderer Berücksichtigung
von Spinfluktuationen - Eine µSR-Untersuchung,"
Ph.D. thesis, 1992.
- Andreas Kratzer,
"Messungen an Uranverbindungen und
Aufbau eines Meßplatzes für gepulste Myonenstrahlen,"
Ph.D. thesis, 1989
Journal articles and conference contributions
E. Frey, F. Schwabl, S. Henneberger, O. Hartmann, R. Wäppling, A. Kratzer and G.M. Kalvius,
"Determination of the Universality Class of Gadolinium,"
Phys. Rev. Lett. 79 (1997) 5142.
G.M. Kalvius, T. Takabatake, A. Kratzer, R. Wäppling, D.R. Noakes, S.J. Flaschin, F.J. Burghart, R. Kadono, I. Watanabe, A. Brückl, K. Neumaier, K. Andres, K. Kobayashi, G. Nakamoto and H. Fujii,
"The influence of impurities and alloying in the Kondo semimetal CeNiSn as seen by µSR,"
Hyperfine Interactions 104 (1997) 157.
H.-H. Klauß, M. Hillberg, W. Wagener, M. Birke, F.J. Litterst, E. Schreier, A. Kratzer, G.M. Kalvius, Y. Haga and T. Suzuki,
"Local magnetic field and muon site in CeAs,"
Hyperfine Interactions 104 (1997) 177.
A. Kratzer, C. Schopf, G.M. Kalvius, H.-H. Klauß, S. Zwirner and J.C. Spirlet,
"µSR investigations of UX3 compounds,"
Hyperfine Interactions 104 (1997) 181.
E. Lidström, R. Wäppling, S.F. Flaschin, G.M. Kalvius, A. Kratzer, D.T. Adroja, B.D. Rainford and A. Neville,
"µSR studies of magnetic properties of CeRhSb and La0.1Ce0.9RhSb,"
Hyperfine Interactions 104 (1997) 193.
M. Ekström, O. Hartmann, A. Marelius, R. Wäppling, E. Schreier, S. Henneberger, A. Kratzer and G.M. Kalvius,
"µSR investigation of single crystalline dysprosium,"
Hyperfine Interactions 104 (1997) 281.
S. Henneberger, E. Schreier, A. Kratzer, L. Asch, G.M. Kalvius, E. Frey, F. Schwabl, O. Hartmann, M. Ekström, R. Wäppling, F.J. Litterst and H.-H. Klauss,
"µSR investigations of gadolinium in the paramagnetic regime near the ferromagnetic transition,"
Hyperfine Interactions 104 (1997) 301.
E. Schreier, S. Henneberger, F.J. Burghart, A. Kratzer, G.M. Kalvius, O. Hartmann, M. Ekström and R. Wäppling,
"High pressure µSR studies on single crystalline gadolinium,"
Hyperfine Interactions 104 (1997) 311.
F.J. Burghart, W. Potzel, G.M. Kalvius, W. Schiessl, A. Kratzer, E. Schreier, A. Martin, M. Hillberg, R. Wäppling and D.R. Noakes,
"Muons and muonium in Zn-spinels,"
Hyperfine Interactions 106 (1997) 187.