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Magnetic Material Characterization via Hystersis (Remote Trigger)
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# Procedure

## Lab Experiment Overall Goals

The goal of this lab exercise is to study the phenomena of magnetic hysteresis and calculate the retentivity, coercivity and saturation magnetization of a material using a hysteresis loop tracer (HLT-111). The remote trigger equipment allows you to control the applied magnetic field (H). By varying this parameter, the J-H loop, dJ/dt and d2J/dt2 loop will be produced.

## Instructions For Simulator

1. Select Sample A or B.
2. Click Plot and the MH curve is displayed on the screen.
3.  Vary the material parameters and observe the characteristics of the material.
4. Reset clears the input field and Reset Figure clears the graph.

## Lab Apparatus

This remote trigger experiment performs experiments on actual hysteresis loop tracer equipment (HLT-111). The experimental setup is housed at Amrita University, Amritapuri Campus and has the following features:

1. The Hysteresis Loop tracer used in this experiment is HLT-111.

2. Observations.

• Diameter of the pick-up coil – 3.21 mm. .
• Gx = 100.
• Gy = 1Sample Used: Thin cylindrical rod made of Commercial Nickel.
• Length of the sample = 37 mm.
• Diameter of sample = 1.17mm.
• Demagnetization factor β= N= 0.0029.

3.The device has been already calibrated.

A. CALIBRATION (SETTINGS):
•  No sample in the pick-up coil
• H balance, DC balance and Phase adjusted for horizontal line in the centre
• Demagnetization (N) at zero
• Area Ratio As/ Ac at 0.399
• Root mean square value of applied magnetic field (Ha) is 209 Gauss
B. CALIBRATION (OBSERVATIONS)
•  Observed value of ex= 7 volts
• Since, the area ratio for the given sample is so small the signal ex was enhanced by multiplying area ratio and demagnetization by three. The finally obtained value of the intercept (below) is divided by this same factor, 3, to give the correct value of coercivity.
• Similarly for calculating G0 we set Area ratio As/Ac to 1.000 and other settings remain as calibrated, the signal ex obtained is, ex = 18 volts.

G0 can be calculated using the relation      ## Lab Procedures

1. Power on the device.

2. Slowly vary the applied magnetic field using magnetic field slider. M-H graph corresponding to the field will be plotted, whenever the slider is stopped.

3. Tabulate the loop width, the tip-to-tip height and positive intercept to negative intercept distance for each magnetic field as shown in the table below.

SL No Magnetic Field(Gauss) Loop Width(mm) Tip-To-Tip Hieght(V) Positive Intercept to Negative Intercept Distance(V)

Table 1: For calculation of coercivity, saturation magnetization and retentivity for the given sample from the loop width, the tip-to-tip height and the positive intercept to negative intercept distance of hysteresis loop respectively

4. Calculation of coercivity:

Plot the loop width of hysteresis loop against magnetic field.

The intercept of the straight line fit on the J-axis gives loop width.
Coercivity,  5. Calculation of saturation magnetisation:

Plot the positive intercept to negative intercept distance against magnetic field.

Find the asymptote and use the equation below:

Saturation magnetisation, 6. Calculation of retentivity:

Plot the tip-to-tip separation against the magnetic field.

Draw asymptote

Retentivity, 7.  Select the M., M.. radio buttons  to observe dJ/dtand d2J/dt2   .

#### Inferences:

1. The obtained value of the coercivity for the given sample is ________ oersted.
2. The obtained value of the saturation magnetisation for the given sample is ________gauss.
3. The obtained value of the retentivity for the given sample is ________ gauss.

Cite this Simulator:

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