ULTRAHIGH-VACUUM COMPATIBLE SUPERCONDUCTING QUANTUM INTERFERENCE DEVICE MAGNETOMETER SYSTEM FOR STUDIES OF MAGNETIC THIN-FILMS

In this article, we describe an ultrahigh vacuum (UHV) compatible supe rconducting quantum interference device (SQUID) magnetometer system fo r investigations of surface, interface, and thin film magnetism. This system provides a new capability for a commercial SQUID magnetometer t o characterize freshly deposited thin film samples transported from a separate molecular-beam epitaxy deposition facility without breaking v acuum. Magnetic measurements can be performed over a wide range of tem peratures down to 4.2 K in applied magnetic fields as high as 1 T, and under a variable vacuum environment in which pressures as low as 10(- 10) Torr can be achieved. The combination of the extremely high sensit ivity of the SQUID for magnetic measurements with UHV analysis techniq ues offers the unique capability for films to be prepared, processed, and characterized repeatedly without substantial contamination. The ca pabilities of the UHV-SQUID magnetometer system are demonstrated by in situ measurements of the magnetic properties of Co/CoO bilayered thin films grown on Si(100) single-crystal substrates by electron-beam eva poration. (C) 1995 American Institute of Physics.