Electromagnetic ultrasound generators and detectors

Magnetostriction is the dimensional change (strain) which accompanies the domain movement and rotation of magnetization. When the magnetio field vibrates so does mag-netostriotion, and as a result ultrasonic waves are produced. A magnetostrictive transducer (MART) is a transducer in a non-contact US instrument where the coated sample 

It should be noted that many of the former studies on US-based detection were carried out by using piezoelectric transducers in contact with the sample [18,19]. Some, however, used non-contact electromagnetic transducers [20] and eddy current testing [21]. The greatest restrictions of the latter are that they require an electrically conductive sample and highly precise positioning of the transducer near the sample. 

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