We analyse the phase transition between the Bragg Glass and the Disordered phase in the vortex lattice in type-II superconductors, both by analytical computations and experimental investigations. It is known that if the Peak Effect can be detected, a Bragg Glass/Disordered phase transition takes place. We show that, in some conditions, this transition can occur without the observation of the Peak Effect Phenomenon. We introduce a method based on the 3rd harmonics of the AC magnetic susceptibility to detect the transition also in these cases. Using this method, we obtain an experimental confirmation of the theoretical predictions on sphere shaped V3Si single crystals, in the high fields/low temperatures range too, where previous experimental studies failed to detect the Bragg/Disordered phase transition.
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