The surface of W(100) was studied under ultra-high vacuum at room temperature, using scanning tunnelling microscopy and low-energy electron diffraction. A novel scanning tunnelling microscopy tip of equi-atomic MnNi alloy was used. This material, with a CuAu-I-type crystalline structure, was an antiferromagnet with a high Néel temperature (1140K). A bulk termination was observed, with a pattern of orthogonal so-called domains of p(3 x 1) missing-row reconstructions. An anomalous feature in image acquisition at the atomic scale was noted: namely, that different images were obtained upon reversal of the scanning direction. This effect was thought to result from the particular tip material used.

Atomically Resolved p(3 x 1) Reconstruction on the W(100) Surface Imaged with Magnetic Tips. S.Murphy, J.Osing, I.V.Shvets: Journal of Magnetism and Magnetic Materials, 1999, 198-199, 686-8