target:
Ligand (31P, 63,65Cu, 119Sn, 23Na, 99,101Ru, 29Si, 139La, 121,123Sb, 75As, 195Pt) and on-site (171Yb, 59Co, 57Fe, 55Mn,...) NMR-investigation of 4f-, 5f-, and 3d- intermetallics with unconventional magnetism and/or superconductivity.
purpose:
NMR probes the local spin susceptibility at the NMR nucleus site via the NMR shift. The NMR shift is a tensor reflecting the local magnetic anisotropy at the nucleus site arising from anisotropic- (dipolar and orbital (p-,d- & f- electrons)) and isotropic- (Fermi contact (s electrons)) hyperfine interactions. The spin lattice relaxation rate probes fluctuations of the transfered hyperfine field originating from the (unstable) 4f-, 5f- or 3d magnetic ion (related to the q-dependent imaginary part of the complex dynamic susceptibility)
method:
Broadline field sweep NMR with a very broad range of accessible frequencies (1-500 MHz) enables multinuclear resonance (detection of various NMR sensitive nuclei with field sweeps up to 14 T).
Fourier Transform (FT) NMR.
High Resolution FT NMR (Bruker 400 MHz, Bruker 500MHz)
Temperatures avaiable: 2 K-700 K.
equipment:
-NMR spectrometer
THREE Tecmag (Discovery/Apollo) 2 chanel NMR
spectrometer (up to 1 GHz).
ONE LapNMR Spectrometer (up to 125 MHz)
ONE home build NMR/NQR spectrometer
-NMR probes
VARIOUS home build solid state NMR probes
with calibrated CERNOX temperature
sensors (design NMR SERVICE Dr.M. Braun)
-Magnets and cryostats
JANIS 9 T (9T-SVM-18) cold bore (KF40)
10E-4 homogeneity magnet
1.7 K - 300 K
JANIS 14 T (14T-SVM-15) cold bore (KF40)
10E-4 homogeneity magnet
1.7 K - 300 K
MAGNEX 9.2 T (10E-5 homogeneity) system
warm bore (8.9 cm) magnet plus
decoupled +-0.2 T modulation coil with
JANIS (STVP) He flow crostat
1.7 K - 400 K
Bruker 400 MHz high resolution magnet (10E-9) plus
Oxford He flow cryostat and
high temperature (700 K) probes plus
MAS probes.
JANIS He flow cryostat for NQR measurements