Discussions by Two Authors:
1. Dirk Then, Institut fuer Physikalische und Theoretische Chemie, Tuebingen
2. Carl Masens, Department of Applied Physics University of Technology, Sydney, Australia
How to Determine the Spring Constant for a Cantilever
from the DI SPM Digest, by Dirk Then.
------- Forwarded Message Follows -------
From: "maps"
<maps@if.sc.usp.br>
To:
<spm@di.com>
Subject: spring constant
Date: Mon, 29
Jun 1998 10:19:18 -0300
How can I calculate the spring constant of the cantilever in the case
of silicon nitride (triangle shaped) and cristal silicon (retangle shaped)
grate?
Marcelo de A. Pereira-da-Silva
Dear Marcelo,
for a rectangular cantilever geometry it is easy to calculate the spring constant using the dimensions of the cantilever and its Young's Modulus with the following equation
k = (E*t^3*w) / (4*L^3)
where E is Young=B4s Modulus, t the thickness, w the width and L the
length of the cantilever.
But there are a lot more accurate possibilities to determine the spring
constant of a cantilever. For example one can calculate the spring constant
from the thermal noise of a cantilever. Another posibility is to add a
small mass at the apex of the cantilever. From the occuring resonance frequency
shift you can calculte the spring constant.
For more details look at the following publications:
J.M. Neumeister, Rev. Sci. Instrum. 65, 1994, pp. 2527 J.P. Cleveland, Rev. Sci. Instrum. 64, 1993, pp. 403 H.-J. Butt, Microscopy 169, 1993, pp. 75 H.-J. Butt, Nanotechnology 6, 1995, pp. 1 G. Y. Chen, Rev. Sci. Instrum. 65, (1994), pp. 2532 G. Y. Chen, J. Appl. Phys. 77, (1995), pp. 3618
With best regards
Dirk Then
======================================================
Dirk Then
Institut fuer Physikalische und Theoretische Chemie Auf der Morgenstelle
8
D-72076 Tuebingen
Tel: ++49(0)7071 / 29 78749
Fax: ++49(0)7071 / 29 5490
mail: dirk.then@ipc.uni-tuebingen.de
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Revised: March 11, 2000
Copyright © John W. Cross