Strong interfacial Dzyaloshinskii-Moriya induced in Co due to contact with NiO.

The magnetic properties of NiO/Co/Pt as a function of Co layer thickness were investigated by polar magneto-optical Kerr effect (PMOKE) (magnetometry and microscopy) and Brillouin Light Scattering (BLS) spectroscopy. PMOKE measurements revealed strong surface anisotropy (1.8 mJ/m2) favoring perpendicular magnetic anisotropy and asymmetric domain wall propagation explained by anticlockwise chirality. BLS measurements show that this chirality is induced by strong interfacial Dzyaloshinskii-Moriya interaction (+ 2.0 pJ/m). This is one of the highest values reported so far for Co layers surrounded by different layers. The observed chirality is opposite to what has been found in Co/oxide interfaces. These results and data published earlier, indicate that the strength of interfacial Dzyaloshinskii-Moriya interaction increases with the amount of stoichiometric NiO. Therefore, this work shows that NiO is the source of the interfacial Dzyaloshinskii-Moriya interaction.

Clinicopathological study of pilomatricoma.

OBJECTIVE: To study the clinical and histopathologic spectrum of pilomatricoma, the benign tumor of hair matrix. METHODS: Retrospective review of 27 cases of pilomatricoma (Calcifying epithelioma of Malherbe) reported at Bahrain Defence Force Hospital from 1993-1999. RESULTS: Most of the cases were confused clinically with sebaceous cysts. Seventy eight per cent of the cases occurred below the age of 30 years. Female to male ratio was 5:4. Head, neck and upper limb were the most common sites for pilomatricoma. The size of the tumors ranged from between 4-35 mm in diameter. Tumors were encapsulated and solid composed of shadow and basophilic cells, and stroma containing varying amounts of calcification, ossification and inflammatory cells. CONCLUSION: Pilomatricomas have a wide variety of clinical characteristics and are often misdiagnosed with other skin conditions. They should be considered along with other benign and malignant conditions in the clinical differential diagnosis of solitary firm skin nodules especially those, which occur in the head, neck and upper limb.