Real and k-space microscopy of CMR manganites
One of the major challenges of contemporary physics is to gain insight into many-body problems such as high
temperature superconductivity displayed by e.g. various cuprates. A similar group of materials are the manganites
that display an equally poorly understood phenomenon; at the transition temperature there is a drop in resistivity
of several orders of magnitude accompanied by a para- to ferromagnetic transition. This is called the colossal
magnetoresistant (CMR) effect.
In the QEM group we investigate the bilayered CMR manganite
La2-2xSr1+2xMn2O7 (LSMO), with various doping levels by means of
angle resolved photoemission and scanning tunneling microscopy and spectroscopy. In order to do so,
we use our own lab systems, the FAMoS and the Createc Ultra High Vacuum - Low Temperature
(UHV-LT) STM, and synchrotron radiation provided by BESSY (Berlin, DE)
and the SLS (Villigen, CH). A measurement of the Fermi surface of LSMO is shown below left as well as a typical
energy distribution map in the XMY-direction. The topographic images taken on a Bi-2212 high Tc superconductor to test the STM/S system (right) show the atomic registery of the Bi atoms and characteristic incommensurate supermodulation.
The single crystals measured are home-grown
with an optical floating zone furnace by YingKai Huang, the crystal grower in our group.
 1.) Fermi surface
of LSMO |
 2.) EDM in the XMY-direction |
 3.) Bi-2212 (27-6-2007) |
 4.) Bi-2212 (15-7-2010) |
This project is the main focus of the PhD research carried out by Sanne de Jong and Freek Massee. For more information, please contact Freek Massee or Mark Golden
