  It has been recently reported that some non-magnetic materials in bulk state,
exhibit magnetic behavior at the nanscale due to surface and size effects. The
experimental observation of these effects is based on the measurement of very
small magnetic signals. Thus, some spurious effects that are not critical for
bulk materials with large magnetic signals may become important when measuring
small signals (typically below 0.0001 emu). Here, we summarize some sources of
these small magnetic signals that should be considered when studying this new
nanomagnetism
