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Magnetic Hysteresis

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 👉 Introduction:- •Magnetic hysteresis is an important phenomenon observed in ferromagnetic materials such as iron, cobalt and nickel. It explains the behavior of a magnetic material when it is magnetized and demagnetized repeatedly. The term “ hysteresis ” means “lagging behind.” In this process, the magnetization of a material does not immediately follow the applied magnetic field but lags behind it. 👉Magnetisation Process:- •When a ferromagnetic material is placed inside an external magnetic field, the tiny magnetic domains inside the material start aligning in the direction of the field. As the strength of the magnetic field increases, more domains align themselves, and the material becomes strongly magnetized. At a certain stage, all domains become aligned and the material reaches magnetic saturation. 👉Retentivity and Coercivity:- •If the external magnetic field is now reduced to zero, the material does not lose all of its magnetism immediately. Some magnetism still remains...
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PN Junction Diode

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  👉Definition:-   •A PN junction diode is one of the most important semiconductor devices used in electronics.  • When a p-type semiconductor is joined with n-type semiconductor; the arrangement so formed is known as PN Junction Diode. •The p-region contains holes as majority charge carriers ; while the n- region contains electrons as majority charge carriers. 👉Formation of PN junction:- •When p-type and n-type semiconductors are joined together , electrons from the N-side start moving towards P-side; and holes from P-side moving towards N-side. •Due to this  movement of charge carriers recombination takes place near the junction.As a result a thin region is formed around the junction where no free charge carriers are present.  •This region is called Depletion region or the layer formed is called Depletion Layer. •The depletion layer creats a potential barrier which opposes the further movement of electrons and holes. 👉Depletion region:- •The depletion r...
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Atomic Force Microscopy (AFM)

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 Atomic Force Microscopy (AFM) Principle, Working, Types, Advantages and Applications 👉What is Atomic Force Microscopy (AFM)? •Atomic Force Microscopy (AFM) is a high-resolution type of scanning probe microscopy technique that allows imaging , measuring and manipulating matter at nanoscale . •AFM can analyze both conducting and non-conducting samples , which makes it highly useful in chemistry, material science, and nanotechnology . 👉Principle of Atomic Force Microscopy:- •AFM works on the principle of measuring the interatomic forces between a sharp probe tip and the sample surface. •A sharp tip (made of Si or Silicon nitride );  attached to a cantilever , scans the sample surface. •When the tip approaches the surface: Forces like Vander wall , electrostatic ,attractive or repulsive forces act between the tip and sample. •These forces cause deflection of the cantilever. •The deflection is detected using a laser–photodiode system . •The detected signal is processed to ge...
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