Epitaxial films of hcp Tb(0001) on bcc W(110) substrates are prepared and their geometric, electronic and magnetic properties are studied. The atomic flatness and cleanness and the single-crystalline state of the W(110) substrates and the Tb films are checked using scanning tunneling microscopy (STM), Auger electron spectroscopy (AES) and low-energy and high-energy electron diffraction (LEED and RHEED). Using electron capture spectroscopy (ECS), the surface electron spin polarization of the Tb(0001) films is studied as a function of temperature. The topmost layer is found to order ferromagnetically below a surface Curie temperature T$\sb{\rm C\sb s}$ = 249.96 K, which lies above both the bulk Curie and Neel temperatures T$\sb{\rm C\sb b}$ = 220 K and T$\sb{\rm N\sb b}$ = 228 K, respectively, and exhibits strongly non-monotonic behavior close to 245 K. Novel critical behavior is observed near T$\sb{\rm C\sb s}$, suggesting strong surface anisotropies, in accord with a recently predicted and previously unobserved surface phase transition.
| Identifer | oai:union.ndltd.org:RICE/oai:scholarship.rice.edu:1911/13298 |
| Date | January 1988 |
| Creators | Jin, Changming |
| Contributors | Rau, C. |
| Source Sets | Rice University |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | 104 p., application/pdf |
Page generated in 0.1001 seconds