Negative tunneling magnetoresistance by canted magnetization in MgO/NiO tunnel barriers

The influence of insertion of an ultra-thin NiO layer between the MgO barrier and ferromagnetic electrode in magnetic tunnel junctions has been investigated by measuring the tunneling magnetoresistance and the X-ray magnetic circular dichroism (XMCD). The magnetoresistance shows a high asymmetry with respect to bias voltage, giving rise to a negative value of -16% at 2.8 K. We attribute this to the formation of non-collinear spin structures in the NiO layer as observed by XMCD. The magnetic moments of the interface Ni atoms tilt from the easy axis due to exchange interaction and the tilting angle decreases with increasing the NiO thickness. The experimental observations are further support by non-collinear spin density functional theory

Cervical mature teratoma 17 years after initial treatment of testicular teratocarcinoma: report of a late relapse

BACKGROUND: Late relapses of testicular germ cell tumor are uncommon. We report a case of cervical mature teratoma appeared 17 years after treatment of testicular teratocarcinoma. CASE PRESENTATION: A 20- year- old patient underwent left sided orchiectomy followed by systemic therapy and retroperitoneal residual mass resection in 1989. He remained in complete remission for 200 months. In 2005 a huge left supraclavicular neck mass with extension to anterior mediastinum appeared. Radical surgical resection of the mass was performed and pathologic examination revealed mature teratoma. CONCLUSION: This is one of the longest long-term reported intervals of a mature teratoma after treatment of a testicular nonseminoma germ cell tumor. This case emphasizes the necessity for follow up of testicular cancer throughout the patient's life