Static magnetization study of κ-(BEDT-TTF)2Cu[N(CN)2]Cl under high pressure. Part 2. Low magnetic fields

Low-field measurements have revealed the presence of paramagnetic contribution to the field-cooled magnetization of single crystal of title salt at pressures as high as 1 kbar and 1.5 kbar. This magnetization appears if field is oriented normal to the conducting ac plane, at temperature just below the onset of bulk SC transition, and saturates at fields of a few Oc. Depending on thermal history, it can even dominate over the diamagnetic Meissner signal. This behavior is similar to recently discovered (due to study of HTSC oxides), intensively studied but still remaining not understood Wohlleben effect (or paramagnetic Meissner effect). For the κ-(BEDT-TTF)2Cu[N(CN)2]Cl we propose that the coexisting magnetic phase might be a cause for the phenomenon.