5614 Posted February 18, 2005 Author Share Posted February 18, 2005 I got the response from maxtor (company who made the hard drive) Hello Jonathan' date=' The [u']backing material for the magnet is nickel/phosphorous plated steel, and is attached using an acrylate based adhesive.[/u] I hope this information is useful to you. Kind regards, Steven Lai, Technical Support Team, Maxtor Ireland LTD. any thoughts? by "the backing material" does he mean the stuff coating the magnet? Link to comment Share on other sites More sharing options...
5614 Posted March 4, 2005 Author Share Posted March 4, 2005 I emailed maxtor asking as to what the metal was that the magnet is attached to... reply was: "We are currently retrieving the information requested." so I will post here again when I know the answer. Link to comment Share on other sites More sharing options...
Johnny5 Posted March 4, 2005 Share Posted March 4, 2005 Just out of curiosity why are you so interesed in magnetic fields, and shielding things from magnetic fields. I know a thing or two about the phenomenon you spoke of. Regards Link to comment Share on other sites More sharing options...
5614 Posted March 4, 2005 Author Share Posted March 4, 2005 I am interested only because I cannot explain nor think of a logical explanation. I mean, shielding is fine, but why does adding a second piece of metal cancel the shielding? and why when i take another piece of the same metal and same magnet does the shielding not occur? (the only difference is the glue, which shouldnt effect the magnetic field at all.) I'm just interested... Link to comment Share on other sites More sharing options...
Johnny5 Posted March 4, 2005 Share Posted March 4, 2005 I'm just interested... Then we have a common interest, exactly why are you interested? Regards Link to comment Share on other sites More sharing options...
5614 Posted March 4, 2005 Author Share Posted March 4, 2005 Everything has an explanation, it's just a case of knowing it... I do not know the explanation for the phonomena I have discovered, being related to magnetic field and magnetic shielding I thought someone who knew that area of physics may be able to help, hence I asked here. Link to comment Share on other sites More sharing options...
Johnny5 Posted March 4, 2005 Share Posted March 4, 2005 Everything has an explanation, it's just a case of knowing it... I do not know the explanation for the phonomena I have discovered, being related to magnetic field and magnetic shielding I thought someone who knew that area of physics may be able to help, hence I asked here. I really didn't read the whole thread. Can you give me the whole phenomenon in a paragraph or so, and pay particular attention to that part of the phenomenon which is most confusing, so I can think about it. For all you know, the glue is a high temperature superconductor. Regards Link to comment Share on other sites More sharing options...
5614 Posted March 4, 2005 Author Share Posted March 4, 2005 The backing material for the magnet is nickel/phosphorous plated steel, and is attached using an acrylate based adhesive. (not really a superconductor!) Summary: Go to post #23 and look at the picture and read the small para below it, then you'll know where in a hard drive I'm talking about. Read post #1 and #5 They're long, but its not easy to explain fully and quickly, if I don't explain fully we'll go in circles for a bit and that's a waste of time and I can't really condense those two posts much. Link to comment Share on other sites More sharing options...
Johnny5 Posted March 4, 2005 Share Posted March 4, 2005 The backing material for the magnet is nickel/phosphorous plated steel' date=' [u']and is attached using an acrylate based adhesive[/u]. (not really a superconductor!) Summary: Go to post #23 and look at the picture and read the small para below it, then you'll know where in a hard drive I'm talking about. Read post #1 and #5 They're long, but its not easy to explain fully and quickly, if I don't explain fully we'll go in circles for a bit and that's a waste of time and I can't really condense those two posts much. Ok I've read it fairly thoroughly too. Let me see if I understand you. You took apart a hard drive. Inside you found this object, the metal is nickel phosphorous plated steel, and the magnet is neodymium iron boron (NIB). The NIB magnet is attached to the nickel plate, using some unknown acrylic adhesive. Then you tested the magnetic field. You found that there is a field above the NIB magnet, but underneath the nickel plate, you observe no magnetic field. You then took a second piece of nickel plate, and put it above the NIB magnet. And after you did this, you again checked the magnetic field. This time, you found magnetic field everywhere. As if the second nickel plate reflected some of the initial field (so that there is now a nonzero B field underneath the acrylic substance+nickle plate) and there is B field above nickel plate 2, so some of the field lines are passing through it. But in the original configuration, B field lines don't pass through the acrylic. Did I understand all of this correctly. Do you think it could have something to do with the magnetic vector potential? Just asking. Regards Link to comment Share on other sites More sharing options...
5614 Posted March 5, 2005 Author Share Posted March 5, 2005 Well Maxtor tech support said: "The backing material for the magnet is nickel/phosphorous plated steel, and is attached using an acrylate based adhesive." Now by "backing material" does he mean what the magnet is coated in or what the magnet is stuck to... I don't know... I have asked again as to what the magnet is stuck to and they are currently in the process of finding out (they told me that on friday - as in yesterday) Other than that you understood it all correctly... I don't see how magnetic vector potential could be associated, well, obviously it is associated, but how can it provide an explanation? Link to comment Share on other sites More sharing options...
Johnny5 Posted March 5, 2005 Share Posted March 5, 2005 Well Maxtor tech support said: "The backing material for the magnet is nickel/phosphorous plated steel' date=' and is attached using an acrylate based adhesive."[/i'] Now by "backing material" does he mean what the magnet is coated in or what the magnet is stuck to... I don't know... I have asked again as to what the magnet is stuck to and they are currently in the process of finding out (they told me that on friday - as in yesterday) Other than that you understood it all correctly... I don't see how magnetic vector potential could be associated, well, obviously it is associated, but how can it provide an explanation? A couple of things. First, I went home and thought about this last night. 1. I think the glue is nothing more than that. The magnet needed to be mounted into place, and so glue was needed I don't think there is anything special about the glue. 2. Here is an article that would be worth reading, or something similiar... Study of magnetic properties of nickel-phosphorus alloy from 1K to 300K 3. Well, without actually knowing the form of the B field, I really cannot say precisely how it comes into play if at all. And for what it is worth, classical electromagnetism isn't the last word on what is responsible for magnetism by any means. I suppose this is wrong, but I usually imagine magnetic particles flowing through the field lines, to give them some kind of reality. Lines are just for a mental picture, and similarly with magnetic monopoles. And by the way, electrodynamics was originally formulated with magnetic monopoles, that experienced a force F=qB, where q was magnetic charge. At any rate, what I would like to ask you, is how did you figure out the shape of the field, did you use a compass, iron filings what? Regards Link to comment Share on other sites More sharing options...
5614 Posted March 5, 2005 Author Share Posted March 5, 2005 I don't have a subsciption to that website and I'm not intending on getting one, if you do have one then could you help me get it? I agree with you about the glue. What I know about the field lines was worked out using a bar magnet with labelled north/south and just a piece of metal to detect a magnetic field... I also used a tiny mini-padlock key on a keychain (so it could freely swing) to see if there was any magnetic field (even a small one). Also read post #15 and #16.... they give more interesting information. Link to comment Share on other sites More sharing options...
Johnny5 Posted March 5, 2005 Share Posted March 5, 2005 Also read post #15 and #16.... they give more interesting information. In post #15 you mention a "magnetic field blocker." What do you think is blocking the magnetic field. The metal? The glue? Regards Link to comment Share on other sites More sharing options...
5614 Posted March 5, 2005 Author Share Posted March 5, 2005 Well if you read post #16 it seemed to rule out the possibility of it being the metal, but logic rules out an acrylic glue causing this... it can't be the magnet itself..... I dont know!!!! Link to comment Share on other sites More sharing options...
Johnny5 Posted March 5, 2005 Share Posted March 5, 2005 Well if you read post #16 it seemed to rule out the possibility of it being the metal, but logic rules out an acrylic glue causing this... it can't be the magnet itself..... I dont know!!!! Could it be the case that there was initially a weak magnetic field under the metal, and you were unable to measure it, and then when you brought in the second piece of metal, you doubled the field strength underneath, and now could measure it? Regards Link to comment Share on other sites More sharing options...
5614 Posted March 5, 2005 Author Share Posted March 5, 2005 No, there is no magnetic field under there, I am positive, or at least if there is it can't even effect 0.5g of metal (which is attracted to magnets)... if there was a magnetic field it'd be as strong as the air is solid.... I am sure its not there. Why would the addition of a second peice of metal double the field strength? Link to comment Share on other sites More sharing options...
Johnny5 Posted March 5, 2005 Share Posted March 5, 2005 No' date=' there is no magnetic field under there, I am positive, or at least if there is it can't even effect 0.5g of metal (which is attracted to magnets)... if there was a magnetic field it'd be as strong as the air is solid.... I am sure its not there. Why would the addition of a second peice of metal double the field strength?[/quote'] Have you tried using a compass needle? As for it doubling the field strength, I don't really think it would, just asking if you thought so. It's very hard without having everything in front of me to tell you what's going on, but I can't help but think this is some kind of basic problem in magnetism. Regards Link to comment Share on other sites More sharing options...
5614 Posted March 5, 2005 Author Share Posted March 5, 2005 Have you tried using a compass needle? Well well... I'd never have guessed... the compass needle is effected by it, not much, but a tiny bit... the field is too small to effect 0.5g of metal, too small to effect even 1ml of ferrofluid, but it does effect a compass needle. Now the NIB we're talking about is big, about 1.5inch or 4cm and its powerful! So what causes 99.9% of the field to be lost through the piece of metal? And then when you place a 2nd piece of metal there the field becomes full strength, its soo weak, can't even effect 1mm of ferrofluid, but it does effect a compass.... what causes such a massive magnetic field blocking? (and why when the 2nd piece of metal is added does that remove the shielding effect?) Link to comment Share on other sites More sharing options...
Johnny5 Posted March 5, 2005 Share Posted March 5, 2005 Well well... I'd never have guessed... the compass needle is effected by it' date=' not much, but a tiny bit... the field is too small to effect 0.5g of metal, too small to effect even 1ml of ferrofluid, but it does effect a compass needle. Now the NIB we're talking about is big, about 1.5inch or 4cm and its powerful! So what causes 99.9% of the field to be lost through the piece of metal? And then when you place a 2nd piece of metal there the field becomes full strength, its soo weak, can't even effect 1mm of ferrofluid, but it does effect a compass.... what causes such a massive magnetic field blocking? (and why when the 2nd piece of metal is added does that remove the shielding effect?)[/quote'] I realize that this is your whole question, the one you want answered. When you bring the second piece in, do you place it in contact with the magnetic, or as you bring it in, does the field strength slowly increase (watch the needle) Regards Link to comment Share on other sites More sharing options...
5614 Posted March 5, 2005 Author Share Posted March 5, 2005 OK, i've got the compass on the table, lets take all reading from the right hand side of the compass, so currently the right is facing East (E)... look at the pic in post #15 if i put the metal like that pic small side touching the NIB at the top then i get N if i put the metal like that pic small side touching the NIB at the bottom then i get S if i put the metal covering the whole NIB then i get W it will not go in the middle, some kinda repulsion - the piece of metal will not go onto the center of the NIB. As for the "does the field strength slowly increase" question the answer is YES, the compass slowly moves from E to wherever its going (see above scenarios) slowly depending on the distance between the NIB and metal. Link to comment Share on other sites More sharing options...
5614 Posted March 8, 2005 Author Share Posted March 8, 2005 Hello Jonathan' date=' The answer that I have received in relation to your question is steel, the piece of metal is made of steel. Hope that is helpful to you. Kind regards, Steven Lai, Technical Support Team, Maxtor Ireland LTD.[/quote'] (That's referring to the metal the NIB is glued to) Anyone got any new ideas? I mean, its some kind of shielding that isn't 100% complete, but why does adding a 2nd piece of metal cancel the shielding effect? Link to comment Share on other sites More sharing options...
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