Two-Dimensional Surface Magnetism in the Bulk Paramagnetic Intermetallic Alloy CoAl(100)
Abstract
Utilizing a combination of the in situ magneto-optical Kerr effect and scanning tunneling microscopy and spectroscopy measurements, we show that the (100) surface of the B2 bulk paramagnetic CoAl is an excellent representation of a two-dimensional ferromagnet. The order-parameter critical exponent β=0.22±0.02 is determined, which is the universal signature of a finite-size two-dimensional XY behavior. The Curie temperature is found to be Tc=90K. The magnetism can be explained by the appearance of Co antisite atoms at the surface.
- Publication:
-
Physical Review Letters
- Pub Date:
- January 2007
- DOI:
- 10.1103/PhysRevLett.98.037202
- Bibcode:
- 2007PhRvL..98c7202R
- Keywords:
-
- 75.70.Rf;
- 71.20.Lp;
- 75.40.Cx;
- Surface magnetism;
- Intermetallic compounds;
- Static properties