AC Susceptometer System
While the principles of the ac susceptibility technique are relatively simple and well understood, there are still numerous possible variations in construction of practical susceptometer devices. The construction of our CryoBIND devices primarily targets the problem of sensitivity, a decisive quantity in measurements of small magnetic signals. In many cases the signals are small either due to the reduced sample volume (small single crystals, thin films) or it is small due to intrinsic reasons (like in paramagnets far above their ordering temperature). Design of the sample/sensor core of our susceptometry provides an inherent thermal stability revealing, depending on the model, very small or entirely suppressed offset voltages. The system design and construction, involved instrumentation, together with offset compensation, are all responsible for unsurpassed sensitivity of our integrated measuring systems: Expressed in equivalent magnetic moment it reaches almost 10exp-9 EMU. Noteworthy, the CryoBIND devices reach this sensitivity level, more commonly approached by the use of SQUID instrumentation, in very small measuring magnetic fields and in the frequency range of the driving field below 1 kHz. CryoBIND systems integrate low-helium consumption nitrogen-jacketed glass, all-fibreglass, or stainless steel dewars. Depending on the model there are either manual or software control over the particular mechanical functions (sample positioning, vacuum valve settings). Measuring systems are delivered with powerful software for measurement execution and data acquisition.